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SOLID FP7 248629 2012-04-01

D8.2 – Second Annual Activity Report

©2011 SOLID-1103-D8.2 PUBLIC of 73

Future and Emerging Technologies

Solid State Systems for Quantum Information Processing

Contract Number: ICT- FP7 248629

2ND ANNUAL ACTIVITY REPORT Period: February 2011 – 31 January 2012

Deliverable D8.2 WP8 – Management

Author(s): Coordinator (Chalmers); Partners

Reviewer(s): .............

WP/Task No: WP8 – Management Number of pages: 73

Identifier: SOLID-1203-D8.2 Dissemination level: PU

Issue Date: 1 April 2012 Revision: V1.0

Keywords: Reporting, scientific, financial, resources, activities

Abstract: This second year report summarizes the progress of the SOLID project, presents the activities of the consortium (research, meetings, publications), the achievements of the project activities, the status of deliverables and milestones, and following up the deployment of resources compared to plan. Potential deviations from the work plan are reported and corrective actions implemented or proposed.

Approved by the Project Coordinator: 1 April 2012

Date of Delivery to the EC: 1 April 2012

SOLID FP7 248629 2012-04-01



Table of Contents

TABLE OF CONTENTS 2

I. DECLARATION BY THE REPRESENTATIVE OF THE PROJECT COORDINATOR 4

II. PUBLISHABLE SUMMARY 5

III. PROJECT OBJECTIVES FOR THE PERIOD 6

III.1. Overview of the overall project objectives 6

III.2. Specific objectives set for the second year period (GW; new Y2 text below) 6

III.3. Summary of work performed by each partner during the second period 7 III.3.1. Summary of the work performed at Chalmers during M13-M24 7 III.3.2. Summary of the work performed at CEA during M13-M24 9 III.3.3. Summary of the work performed at TUD during M13-M24 11 III.3.4. Summary of the work performed at ETHZ during M13-M24 14 III.3.5. Summary of the work performed at KIT during M13-M24 16 III.3.6. Summary of the work performed at IPHT during M13-M24 20 III.3.7. Summary of the work performed at CNRS during M13-M24 21 III.3.8. Summary of the work performed UNIBAS during M13-M24 23 III.3.9. Summary of the work performed at TUM during M13-M24 26 III.3.10. Summary of the work performed at USTUTT during M13-M24 29 III.3.11. Summary of the work performed at SNS during M13-M24 31 III.3.12. Summary of the work performed at UPV/EHU during M13-M24 34

III.4. WP1 – Josephson junction (JJ) qubits (Chalmers) 37 III.4.1. Deviations and corrective actions 37 III.4.2. Work in WP1 during Y3 37

III.5. WP2 – Semiconductor spin qubits (TUD) 37 III.5.1. WP2 Deviations and corrective actions 37 III.5.2. Work in WP2 during Y3 37

III.6. WP3 – Spin qubits in NV centres in diamond (USTUTT) 37 III.6.1. Deviations and corrective actions 37 III.6.2. Work in WP3 during Y3 38

III.7. WP4 – Hybrid devices and quantum interfaces (CEA) 38 III.7.1. Deviations and corrective actions 38 III.7.2. Work in WP4 during Y3 38

III.8. WP5 – Solid-state quantum technologies (IPHT) 38 III.8.1. Deviations and corrective actions 38 III.8.2. Work in WP5 during Y3 39

III.9. WP6 - Dissemination, training and integration (TUM) 39 III.9.1. WP6 Deviations and corrective actions 39 III.9.2. Work in WP6 during Y3 39

III.10. WP7 – Assessment of systems integration and operation (KIT) 40

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IV. DELIVERABLES AND MILESTONES TABLES 41 Table of Deliverables from start of the project 41 Table of Milestones for the second period 42

V. PROJECT MANAGEMENT (WP8 – CHALMERS – GÖRAN WENDIN) 46

V.1. WP8 objectives 46

V.2. Consortium Management tasks and achievements 46

V.3. WP8 Deliverables and milestones 47

V.4. List of Meetings during the period 47

V.5. Project planning and status 48

V.6. Deviations and corrective actions 48

V.7. Explanation of the use of the resources (Y2: 1 Feb 2011-31 jan 2012) 49 V.7.1. Direct costs items for beneficiary 1 (Chalmers) 49 V.7.2. Direct costs items for beneficiary 2 (CEA) 49 V.7.3. Direct costs items for beneficiary 3 (TUD) 50 V.7.4. Direct costs items for beneficiary 4 (ETHZ) 50 V.7.5. Direct costs items for beneficiary 5 (KIT) 51 V.7.6. Direct costs items for beneficiary 6 (IPHT) 51 V.7.7. Direct costs items for beneficiary 7 (CNRS) 52 Direct costs items for beneficiary 7 (UJF, 3rd party SC 10, linked to CNRS) 52 V.7.8. Direct costs items for beneficiary 8 (UNIBAS) 53 V.7.9. Direct costs items for beneficiary 9 (TUM) 53 V.7.10. Direct costs items for beneficiary 10 (USTUTT) 54 V.7.11. Direct costs items for beneficiary 11 (SNS) 54 V.7.12. Direct costs items for beneficiary 12 (UPV/EHU) 55

VI. FINANCIAL STATEMENTS 55

VII. CERTIFICATES 55

VIII. REFERENCES 55

IX. ANNEX: OUTREACH AND PUBLICATIONS 56

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©2011 SOLID-1103-D8.2 PUBLIC Page 4 of 73

I. Declaration by the representative of the project coordinator Official EC form to be signed and attached here ! (coordinator only)

I, as scientific representative of the coordinator of this project and in line with the obligations as stated in Article II.2.3 of the Grant Agreement declare that:

§ The attached periodic report represents an accurate description of the work carried out in this

project for this reporting period;

§ The project:

□ X has achieved most of its objectives and technical goals for the period with relatively minor deviations.

§ The public website:

□ X is up to date

§ To my best knowledge, the financial statements which are being submitted as part of this report are in line with the actual work carried out and are consistent with the report on the resources used for the project (section 3.4) and if applicable with the certificate on financial statement.

§ All beneficiaries, in particular non-profit public bodies, secondary and higher education establishments, research organisations and SMEs, have declared to have verified their legal status. Any changes have been reported under section V (Project Management) in accordance with Article II.3.f of the Grant Agreement.

Name of scientific representative of the Coordinator: Göran Wendin

Date: 01/4/2012 Göran Wendin

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II. Publishable Summary SOLID is a EU-funded collaborative RTD project (FP7-ICT-FET-248629) officially launched on February 1st, 2010. SOLID is part of the Future and Emerging Technologies (FET) proactive initiative on Quantum Information Technology (QIT). The SOLID concept is to develop small coherent solid-state hybrid systems with 3-8 qubits capable of performing elementary processing and communication of quantum information. This involves design, fabrication and investigation of combinations of qubits, oscillators, cavities, and transmission lines, creating hybrid devices interfacing different types of qubits for quantum data storage, qubit interconversion, and communication. The SOLID main idea is to implement small solid-state pure and hybrid QIP systems on common platforms based on fixed or tunable microwave cavities and optical nanophotonic cavities. Various types of solid-state qubits will be connected to these "hubs": Josephson-junction circuits, quantum dots and NV centres in diamond. The approach can immediately be extended to connecting different types of solid-state qubits in hybrid devices, opening up new avenues for processing, storage and communication.

Major SOLID challenges involve: Scalability of quantum registers; Implementation and scalability of hybrid devices; Design and implementation of quantum interfaces; Control of quantum states; High-fidelity readout of quantum information; Implementation of algorithms and protocols The SOLID software goal is to achieve maximal use of the available hardware for universal gate operation, control of multi-qubit entanglement, benchmark algorithms and protocols, implementation of teleportation and elementary error correction, and testing of elementary control via quantum feedback. An important SOLID goal is also to create opportunities for application-oriented research through the increased reliability, scalability and interconnection of components. During the second year there has been oustanding SOLID progress: • Superconducting quantum information circuits using Josephson-junction (JJ) based qubits have

entangled 3 qubits, implemented a Toffoli gate, performed state tomography as a preparation for teleportation and error correction, developed multiplexed readout of qubits, demostrated quantum speedup for the Grover algorithm, entangled qubits with two-level fluctuators (TLF), developed microwave technologies, and developed applications toward metamaterials.

• Work on scalable architectures is progress, and circuits with 4 transmon qubits coupled to a common bus and with individual multiplexed qubit readout is being tested.

• Transmon qubit in 3D cavity with nearly 100 microseconds coherence time. • Qubit lasing investigated experimentally and theoretically. • Optimal control of quantum processors investigated theoretically. • Strong coupling gates investigated theoretically. • Hybrid circuits involving NV centers, Er/Nd-doped crystallites, or quantum dots coupled to

superconducting resonators have demonstrated potential for memory and interface applications. • Research on NV centers continue to show great progress and promise, including entaglement of several

NV centers and dynamic decoupling to prolong phase coherence. • Photonics with quantum dots and quantum wires shows great promise for spin-photon interfaces. • More than 100 peer-reviewed papers published. • More than 25 papers in Nature, Science and high-impact letter journals. • More than 80 invited talks and lectures at conferences and schools. • A training exchange program for young scientists with so far 10 visits to partner laboratories. • Organization of a topical workshop on superconducting QIP in Delft, and a SOLID general workshop in

Grenoble. • 3 PhD theses and 11 MSc theses within the field of solid-state quantum information processing.

This shows that SOLID has taken decisive steps toward small-scale implementations of quantum information processing with solid-state devices. By the end of the third year (early 2013), there is a good chance that SOLID will have demonstrated proofs-of-concept of useful scalabable quantum information processing, as well as the first examples of genuine hybrid devices with potential for information storage.

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III. Project Objectives for the period

III.1. Overview of the overall project objectives The SOLID objectives are to design, fabricate, characterise, combine, and operate solidstate quantum-coherent registers with 3-8 qubits based on three major types of qubits: (1) JJ qubits, (2) QD/spin qubits, and (3) NVC spin qubits. Overall SOLID objectives are:

• Scalability of quantum registers • Implementation and scalability of hybrid devices • Design and implementation of quantum interfaces • Control of quantum states • High-fidelity readout of quantum information • Implementation of algorithms and protocols

An important goal of SOLID is to create opportunities for application-oriented research through the increased reliability, scalability and interconnection of components that is at the heart of the SOLID agenda. The SOLID applied objectives are to develop the solid-state core-technologies:

• Microwave engineering • Photonics • Materials science • Control of the dynamics of small entangled quantum systems

III.2. Specific objectives set for the second year period (GW; new Y2 text below) For a complete list of detailed S&T objectives we refer to deliverables D1-D7, presenting full acounts of research during Y2. Below we list a representative set of objectives:

• Design, fabricate, characterise and operate scalable multi-qubit (≥3) registers with readout of individual qubits coupled through a common oscillator bus.

• Develop and implement protocols and algorithms. • Demonstrate integrated spin qubit functionality in a two-qubit semiconductor QD device. • Create spin qubits in diamond allowing to observe coherent coupling between individually

addressable electron spins at room temperature. • Design and experimental realization of microscopic-like quantum systems embedded in

microwave resonators: quantum dots in InAs nanowires, quantum wells in nanocavity interfaces, NV centers.

• Entangle different kinds of qubits. • Implement elementary logic gates in hybrid systems. • Create long-lived quantum memory based on nuclear spin ensembles. • Create a platform for training of young researchers and scientific. • Perform comparative analysis of different solid-state qubit systems. • Assess SOLID progress and provide feedback and corrective actions.

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III.3. Summary of work performed by each partner during the second period

III .3.1. Summary of the work performed at Chalmers during M13-M24 1.1.1 Quantum registers with transmon qubits coupled through a superconducting resonator (cavity) Chalmers is exploring approaches which can combine the best properties of 2D and 3D cavity qubits. Our approach is to develop a platform for transmon qubits on membranes. For a qubit on a membrane the electrical field is mostly in the vacuum and only a tiny portion of the energy is stored in the membrane. The first samples have been fabricated. The work to characterise the devices will be performed during Y3. 1.2.2 Collaboration on common devices, readout and tunable resonantors There is ongoing discussion, most recently manifested at the SOLID topical workshop in Delft in January 2012. Any concrete collaboration on hardware and software solutions and applications will be reported at the end of the project. 1.2.3 Theory of the JJ parametric-amplifier read-out (Chalmers (T)) We developed theory for nonlinear parametric amplifier based on a tunable superconductive strip line resonator. The parametric effect is achieved by rapid modulation of the magnetic flux through the SQUID integrated with the resonator. We derived and analyzed the equation of motion for the driven resonator, evaluated stability diagrams, position of the bifurcation points, and the squeezing effect. The main attention has been paid to the effects of nonlinearity of the SQUID, which defines the stationary parametric regimes. We investigated both the sub-threshold amplification and multistability regime above the parametric threshold, evaluated the strength of the field inside the cavity and the input-output scattering matrix as functions of frequency detuning, pump amplitude, and the phase shift. The latter allowed us to identify the output quadratures with optimal gains and noise squeezing. This analysis will be applied to identifying the optimal parametric amplification regime, and also the parametric bifurcation regime to be used for qubit readout. 1.3.2 Microscopic models of decoherence sources This task has been (partially) accomplished and reported in Y1. No further work has been done during Y2 because of terminated support from iARPA. The Task is regarded as finished. 4.1.2 Direct superconducting qubit - spin interface (Chalmers(T)) This task has been accomplished and reported in Y1. No further work has been done during Y2. The Task is regarded as finished.

4.5 Quantum communication A new task was started at Chalmers during Y1 directed towards a coherent quantum interface between microwave and optical photons. The experimental activity at Chalmers has focused on the hybrid devices, aiming at coupling rare earth spin ensembles to microwaves. The Post-doc payed by Solid is working on that project. The initial work has focused on coupling a superconducting cavity to a rear earth crystal. In the first experiments we used Erbium doped crystals and could see coupling but we did not quite reach the strong coupling limit. These results were published in Journal of Physics B. Subsequently we have repeated the same experiment with Nd and there we seem to reach the strong coupling regime, these results are still being analyzed. 5.1.1 A General-Purpose Parametric Amplifier (Chalmers(E)) Chalmers is developing a parametric amplifier based on the flux-tunable cavity resonator. Several samples have been tested, but parameters have not yet been optimal. The work is continued during Y3.

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5.1.2 Quantum limited amplification and its relation to qubit read-out (Chalmers(T)) Task finished during Y1. 5.1.3 Scattering of a microwave photons on a single qubit in a transmission line (Chalmers(E+T)) [1,6] We have embedded a single transmon qubit in a transmission line and measured reflection and transmission from the transmon. On resonance we find upto 99.6% extinction in the transmitted field. Using the Autler Towns splitting, we have demonstrated a very fast and efficient single photon router for microwave photons. The router uses so called electromagnetically induced transparency in a superconducting transmon qubit. It has a 99% efficiency and the routing can be done in a few ns. In the same setup, we have also measured the correlations of the reflected and transmitted fields. We observe clear anti bunching in the reflected field with a g2 value of 0.51. In the transmitted field we observe (super) bunching with g2 above 2. The Chalmers theory group has contributed with modeling of the experimental work described above. In particular, we have developed a model describing the effect of a finite bandwidth detector on the second order coherence in the microwaves scattered from a single transmon qubit. The finite bandwidth detector was modeled as a perfect detector after a finite bandwidth two-sided cavity. The model was then solved using the concepts of cascaded quantum systems, where the dynamics is simplified by considering signal flow only in the forward direction. 5.1.4 Josephson Metamaterials The Chalmers group has in an initial step studied the Kerr effect in a single transmon qubit embedded in an open transmission line. There is a substantial Kerr effect; we demonstrate conditional phase shifts up to 8.4 degree per photon, between two modes of coherent microwave fields at the single photon level. The data are being analyzed and the results will be reported in Y3. 5.3.1 Improving coherence times of qubits [5] The Chalmers group has measured the temperature and bias dependence of the charge noise with single electron transistors. Based on the different dependencies we can draw rather strong conclusions on how the two-level fluctuators are activated by the SET. The TLFs seem to be thermally coupled to the SET electron bath. To account for the data, the TLFs must reside in the immediate vicinity of the device, and we can rule out that they are located in the interface between Si and SiO2 or in the bulk dielectric. 5.5.1 Simulation of useful many-body Hamiltonians Theoretical activity planned for Y3. References: 1. Demonstration of a single-photon router in the microwave regime, Io-Chun Hoi, C. M. Wilson, G. Johansson, T. Palomaki, B. Peropadre, and P. Delsing, Phys. Rev. Lett. 107, 073601 (2011). 2. Rare earth spin ensemble magnetically coupled to a superconducting resonator, P. Bushev, A. K. Feofanov, H. Rotzinger, I. Protopopov, J. H. Cole, C. M. Wilson, G. Fischer, A. Lukashenko, A. V. Ustinov, Phys. Rev. B 84, 060501(R) (2011). 3. Towards a coherent quantum microwave to optical photon interface, Matthias Staudt (Chalmers), QIPC 2011, ETH Zurich, September 5 - 9, 2011. 4. Are "pinholes" the cause of excess current in superconducting tunnel junctions? A study of Andreev current in highly resistive junctions, T. Greibe, M.P.V. Stenberg, C.M. Wilson, Th. Bauch, V.S. Shumeiko, and P. Delsing, Phys. Rev. Lett. 106, 097001 (2011) 5. Activation mechanisms for charge noise, M. V. Gustafsson, A. Pourkabirian, John Clarke, and Per Delsing (2012); arXiv 1202.5350 6. Generation of nonclassical microwave states using an artificial atom in 1D open space, Io-Chun Hoi, Tauno Palomaki, Göran Johansson, Joel Lindkvist, Per Delsing, and C M Wilson, arXiv 1201.2269 (2012) 7. Coupling of an erbium spin ensemble to a superconducting resonator, Matthias U Staudt, Io-Chun Hoi, Philip Krantz, Martin Sandberg, Michael Simoen, Pavel Bushev, Nicolas Sangouard, Mikael Afzelius, V Shumeiko, Göran Johansson, Per Delsing and C. M. Wilson, Accepted for publication in Journal of Physics B, (2012)

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III .3.2. Summary of the work performed at CEA during M13-M24 During Y2, CEA has developed SOLID research along three main directions: • Operating the two-qubit processor fitted with high-fidelity single-shot readout that had been developed

during Y1, characterizing quantitatively the effect of decoherence on gate operation, and demonstrating quantum speed-up for the a quantum algorithm, namely the Grover search algorithm on four objects. In parallel, the readout method based on the Josephson Bifurcation Amplifier was investigated more in depth [3-4].

• Designing, fabricating and testing new multi-transmon circuits also fitted with single-shot readout of the qubit register, and with a coupling bus for the qubit-qubit interactions.

• Following the results obtained during Y1 on the strong coupling between a resonator and an ensemble of NV spins, CEA has demonstrated during Y2 the storage and retrieval of a microwave field in a spin ensemble [5]. CEA has then operated a full hybrid structure combining a transmon qubit coupled to a spin ensemble, and demonstrated the coherent transfer of quantum information between the qubit and the spin ensemble [6]. The delicate situation of an inhomogeneous spin ensemble strongly coupled to a cavity was investigated in [7].

1.1.1 Quantum registers with transmon qubits coupled through a superconducting resonator (cavity) CEA has first probed the readout of a small array of 4 linear resonators with staggered frequencies, coupled to a single feed and readout line. In this preliminary experiment, compact lumped element designs, necessary for placing many qubits on a chip, were simulated and probed.

In a second experiment, a full structure with 4 tunable transmons each one measured by a JBA resonator and coupled to a unique feed and readout line was operated. This design allows to perform multiplexed readout of the different qubits at the same time. The transmons are also capacitively coupled to a coupling bus. The four qubits have been read with their JBA resonator, but the multiplexed readout had not been achieved yet. 4.2.1 Josephson qubits coupled to nanocrystals Before operating a full hybrid structure, CEA has performed during Y2 further experiments on the coupling between a microwave cavity and a NV spin ensemble [4]. The experiments performed have demonstrated the coherent transfer of quantum information between the microwave cavity and the spin ensemble, but with a storage time in the spin ensemble severely limited at about 30 ns because of the inhomogeneous broadening of the spins. 5.4 Dynamic and/or algorithmic control of entanglement and other properties of small quantum systems Universal gate operation Task 1.4.1, 1.4.2, 1.4.3; task 2.1.3, 2.4 The universal Sqrt(iSwap) gate was implemented in the 2-qubit processor and its fidelity was quantitatively probed by determining the quantum map associated to the actual gate operation performed [1]. The Chi matrix of this quantum map was determined and analysed quantitatively. Quantum control/algorithms/multi-qubit entangled states of few-qubit systems Task 1.4; task 2.4; task 4.5; task 5.5 Entangled Bell states have been produced and probed using the 2-qubit processor. Although the readout loophole was not closed, the CHSH inequality probing entanglement was violated by many sigmas. Benchmark algorithms and protocols The Grover search algorithm on 4 objects was implemented in the 2 qubit processor [2]. This algorithm benchmarks the processor because an ideal processor should find the answer at each run of the algorithm. We found that the processor provided the exact answer at each run with a probability close to 0.6, significantly larger than the probability 0.25 obtained by picking a random answer, which is the best a classical algorithm can achieve in one algorithmic step. This result, which proves for the first time the

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quantum speed-up for the Grover search algorithm. Elementary control via quantum feedback CEA has not yet carried any work on quantum feedback. References:

[1] Characterization of a two-transmon processor with individual single-shot qubit readout, Dewes et al., Phys. Rev. Lett. 108, 057002 (2012); DOI: 10.1103/PhysRevLett.108.057002

[2] Demonstrating quantum speed-up in a superconducting two-qubit processor, Dewes et al., to be published in Phys. Rev. B., arXiv:1110.5170

[3] Circuit QED with a Nonlinear Resonator: ac-Stark Shift and Dephasing, Ong et al., Phys. Rev. Lett. 106, 167002 (2011) [4] Backaction of a driven nonlinear resonator on a superconducting qubit on a superconducting qubit, Boissonneault et al., Phys. Rev. A, in press, arXiv:1111.0203. [5] Storage and retrieval of a microwave field in a spin ensemble, Kubo et al., Phys. Rev. A 85, 012333 (2012), DOI: 10.1103/PhysRevA.85.012333 [6] Hybrid Quantum Circuit with a Superconducting Qubit Coupled to a Spin Ensemble, Kubo et al., Phys. Rev. Lett. 107, 220501 (201) DOI: 10.1103/PhysRevLett.107.220501. [7] Strongly coupling a cavity to inhomogeneous ensembles of emitters: Potential for long-lived solid-state quantum memories, Diniz et al Phys. Rev. A 84, 063810 (2011), DOI: 10.1103/PhysRevA.84.063810

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III .3.3. Summary of the work performed at TUD during M13-M24 1.1.1 Quantum registers with transmon qubits coupled through a superconducting resonator (cavity) (DiCarlo) Joining SOLID at the Y1 review has let us enhance our development of multi-transmon registers in circuit Q3D (coupling and readout with 3-dimensional cavities) and in traditional circuit QED (coupling and readout of qubits with coplanar waveguide resonators on a chip). In circuit Q3D, we have achieved beyond order-of-magnitude increase in qubit coherence over traditional circuit QED, even slightly surpassing the published state of the art. Our best numbers in a three-qubit device include a qubit relaxation time T1 of 85 µs, and a dephasing time T2 reaching 94 µs with dynamical decoupling. Combining this improvement with our recent addition of a Josephson parametric amplifier to the readout amplification chain (collaboration with K. Lehnert at JILA-NIST), we have now achieved high-fidelity dispersive qubit readout with few-photon excitations of the cavity. We have reached 97% single-shot fidelity, and quantitatively demonstrated the readout’s projective and quantum-non-demolition character [D. Ristè et al., in preparation (2012)]. As an application, we already use this readout technique to eliminate residual (few-percent) thermal excitation of qubits by post-selection (ibid). We are also pursuing a demonstration of deterministic qubit reset by combining this readout with elementary feedback (in progress). In traditional circuit QED, we have developed a multi-qubit architecture wherein qubits are coupled by a high-quality factor quantum-bus resonator, and each qubit is individually readout with a dedicated resonator. We have started with a two-qubit prototype device that shows excellent (3-4 µs) qubit relaxation and dephasing times for traditional circuit QED. Work in progress focuses on quantitative analysis of simultaneous, frequency-multiplexed qubit readouts. We are also realizing a toolbox of two-qubit gates based on resonant interactions with the quantum bus (5 µs measured photon lifetime), following theory work from the Solano group [G. Haack et al., PRB (2010)].

2.1 Integrated universal spin qubit functionality in semiconductor quantum dots

2.1.1 Quantum dots defined by Schottky gates (Vandersypen)

Following our work last year on integrating independent read-out of two spins with coherent exchange (published in Science, 2011), we have worked to include site-selective single-spin rotations in the same measurement run. We have observed electric dipole spin resonance of the spin in the left and right quantum dot. We found that the resonance lines for the two dots are separated by 35 mT. This permits individual addressing of the two spins. This shift in the resonance condition was not induced by an external magnetic field gradient, but presumably is the result of the different confinement strengths in the two dots, leading to a different degree of renormalization of the g-factor (Zeeman splitting). We could also observe a shift in the resonance condition of EDSR mediated by spin-orbit interation versus EDSR mediated by hyperfine coupling (the latter involves a nuclear spin flop, which costs energy). The electron spin resonance signal was obtained by adiabatic inversion of the spins. In this sample, the alignment of the gate pattern with respect to the crystal axis makes the Rashba and Dresselhaus contributions work against each other and prevented coherent single-spin rotations. In a next sample, this will be remedied and we expect to observe coherent single-spin rotations, in combination with coherent exchange and independent read-out. That should bring us in a position to explore simple quantum protocols in Y3. 2.3 Control of decoherence 2.3.1 Reducing the nuclear field distribution (Vandersypen) 2.3.3 Controlling other noise sources (Vandersypen) 2.3.4 Quantum dots in nuclear-spin-free materials (Vandersypen)

TUD has performed measurements on quantum dots defined by electrostatic gates in Si/SiGe heterostructures. The devices were fabricated in the group of Mark Eriksson (U Wisconsin) and measured in the Vandersypen group. We have seen signatures of Pauli spin blockade, and performed experiments with fast gate voltage pulses. Furthermore, we have applied microwave excitation. We observed that the samples were generally quite unstable, but stability did not degrade upon microwave excitation of upon applying gate

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voltage pulses.

We have been involved as well in measurements performed in the Eriksson group. These focused on single-shot detection of relaxation of two-electron spin states, with lifetimes varying from 10 ms to 3 seconds. This work led to a joint publication (Phys Rev Lett 2012).

For Y3, we will carry out measurements on undoped samples, which have been shown by the HRL group to be significantly more stable than the usual doped samples. The undoped samples are presently being fabricated and tested. 2.4 Implementation of quantum protocols (Vandersypen) To be done in Y3. 3.2 Maximize coherence by dynamical quantum control of qubit and environment (Hanson) 3.2.1 Study decoherence in tailored environments We have in the previous year used multi-pulse dynamical decoupling techniques to study and mitigate the decoherence of an NV spin qubit in an electron spin bath. These techniques have now been transferred to NV spins in a nuclear spin bath, showing that the T1 limit (few ms) can be reached at 300K. The shape of the decay and the coherence time as function of decoupling pulses has been studied 3.2.2 Dynamical control of the qubit and its environment We have combined dynamical decoupling techniques with coherent control of the spin bath environment itself. This way, we have been able to determine the dephasing contributions caused by each of the different types of spins in the environment. Furthermore, we have measured directly the dynamics within the spin bath (bath correlation times). Finally, we have shown that dephasing of the spin qubit can be suppressed through coherent control of the spin bath environment. Results are submitted.

3.3 Develop high-fidelity readout (Hanson) We have achieved the main goal of task 3.3: high-fidelity single-shot readout of a single NV electron spin. For this, we have developend efficient photon collection devices, allowing for up to 10 photons to be detected in one shot from driving a single spin-resolved optical transition on resonance. The readout can discriminate between the spin states with average single-shot fidelity of 93%. Furthermore, we have extended this technique to full single-shot readout of a multiple nuclear spins in diamond. Results were published in Nature. 4.3 Spin-photon interfaces 4.3.2 QW- nanocavity interfaces (Zwiller/Kouwenhoven) Our work on hybrid quantum systems has made important progress with the first demonstration of a frequency locked quantum dot: have implemented a feedback circuit to frequency stabilize the emission from a single quantum dot with a rubidium vapor reference cell. This enables the generation of universally indistinguishable photons and offers a tool to counteract spectral diffusion.

We have studied light extraction efficiency from quantum dots in nanowires and demonstrated that tapering that can be defined during nanowire growth can drastically improve the light extraction efficiency [12]. Using contacted InP nanowire pn junctions containing a quantum dot, we have performed photocurrent measurements under reverse bias where the photocurrent generated by absoprtion in the quantum dot was amplified in the nanowire by avalanche multiplication. The gain we observe in our single nanowire avalanche photodiode is large enough to detect the absorption of a single photon and will enable single shot readout of the charge state of a nanowire quantum dot [13]. 5.2 Photonics (TUM, ETHZ, TUD, USTUTT) 5.2.4 Coupling of NV centers to solid-state photonic structures (Hanson) We have investigated coupling of single NV centers in nanocrystals as well as in a hybrid cavityQED system

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consisting of a single NV center in a nanocrystal positioned inside a GaP photonic crystal cavity. We have observed strong enhancement of NV emission at the cavity resonance [14], which proves the coupling of the NV to the cavity. At the same time, the photonic solid-immersion lens (SIL) structures milled by focused-ion beam (see results in WP3) have enabled us to reach the single-shot readout regime for NV centers in bulk diamond, thereby erasing the need for the nanocrystal approach. We will therefore focus our efforts on the SIL approach for the remainder of SOLID. References: 1. Selective darkening of degenerate transitions for implementing quantum controlled-NOT gates, P.

D. de Groot, S. Ashhab, A. Lupascu, L. DiCarlo, F. Nori, C. J. P. M Harmans, J. E. Mooij, Submitted (2012). Available at http://lanl.arxiv.org/abs/1201.3360.

2. Single-shot measurement of triplet-singlet relaxation in a Si/SiGe double quantum dot ��, J. R. Prance, Zhan Shi, C. B. Simmons, D. E. Savage, M. G. Lagally, L. R. Schreiber, L. M. K. Vandersypen, Mark Friesen, Robert Joynt, S. N. Coppersmith, M. A. Eriksson, Phys. Rev. Lett. 108, 046808 (2012)

3. Single-Shot Correlations and Two-Qubit Gate of Solid-State Spins, ��K. C. Nowack, M. Shafie, M. Laforest, G. E. D. K. Prawiroatmodjo, L. R. Schreiber, C. Reichl, W. Wegscheider, L. M. K. Vandersypen, ��Science 333, 1269 (2011)

4. Coupling artificial molecular spin states by photon-assisted tunnelling, ��L.R. Schreiber, F.R. Braakman, T. Meunier, V. Calado, J. Danon, J.M. Taylor, W. Wegscheider and L.M.K. Vandersypen, �� Nature Communications 2, 556 (2011)

5. Generating Entanglement and Squeezed States of Nuclear Spins in Quantum Dots ��, M. S. Rudner, L. M. K. Vandersypen, V. Vuletić, and L. S. Levitov, �� Physical Review Letters 107, 206806 (2011)

6. C-Phase gate for single-spin qubits in quantum dots, ��T. Meunier, V.E. Calado, L.M.K. Vandersypen, ��Physical Review B 83, 121403 (2011)

7. Single-spin magnetometry with multi-pulse dynamical decoupling sequences, G. de Lange, D. Ristè, V. V. Dobrovitski, R. Hanson, Physical Review Letters 106, 080802 (2011)

8. Spin dynamics in the optical cycle of single nitrogen-vacancy centres in diamond, L. Robledo, H. Bernien, T. van der Sar, R. Hanson, New Journal of Physics13, 025013 (2011).

9. High-fidelity projective readout of a solid-state spin quantum register, Lucio Robledo, Lilian Childress, Hannes Bernien, Bas Hensen, Paul F. A. Alkemade, Ronald Hanson, Nature 477, 547-578 (2011).

10. Controlling the quantum dynamics of a mesoscopic spin bath in diamond, G. de Lange, T. van der Sar, M.S. Blok, Z. H. Wang, V.V. Dobrovitski, and R. Hanson, submitted, see http://arxiv.org/ftp/arxiv/papers/1104/1104.4648.pdf

11. Two-photon quantum interference from separate nitrogen vacancy centers in diamond, H. Bernien, L. Childress, L. Robledo, M. Markham, D. Twitchen, R. Hanson, Physical Review Letters 108, 043604 (2012)

12. Bright single photon source in bottom-up tailored nanowires, Reimer M. E., Bulgarini G., Akopian N., Hocevar M., Bouwes Bavinck M., Bakkers E. P. A. M., Kouwenhoven L. P., Zwiller V.; Accepted for publication in Nature Communications

13. Avalanche amplification of a single exciton in a semiconductor nanowire, Bulgarini G., Reimer M. E. N., Hocevar M., Bakkers E. P. A. M., Kouwenhoven L. P., Zwiller V., Submitted

14. Deterministic nano-assembly of a coupled quantum emitter – photonic crystal cavity system T. van der Sar, J. Hagemeier, W. Pfaff, E.C. Heeres, S.M. Thon, H. Kim, P.M. Petroff, T.H. Oosterkamp, D. Bouwmeester, and R. Hanson Applied Physics Letters 98, 193103 (2011). (Cover article)

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III .3.4. Summary of the work performed at ETHZ during M13-M24 1.1.1 Quantum registers with transmon qubits coupled through a superconducting resonator (cavity) (Wallraff) At ETHZ a circuit QED based platform with three integrated transmon qubits with individual large bandwidth flux and charge control and joint dispersive read-out has been realized. Using this platform ETHZ has demonstrated the coherent part of a teleportation protocol up to the read-out step (PRL, January 2012) and a three qubit Toffoli gate (Nature, January 2012), which is an important primitive in the context of quantum error correction. 2.1.2 Self-assembled quantum dots (Imamoglu) At ETHZ a novel sample geometry was designed and fabricated allowing for simultaneous irradiation of the QD with microwave and optical fields in order to investigate spin resonance of a single electron in a charge tunable QD. In a preliminary experiment the electric field of the microwaves contained in a coplanar waveguide was coupled to the exciton in a QD, which led to the observation of photon sidebands. 2.3.1 Reducing the nuclear field distribution (Imamoglu) In addition to developing electron-spin-resonance to accurately determine and monitor the Overhauser field distribution, we are working on implementing homodyne measurement of spin-flip Raman scattering: since spontaneous Raman scattered light has coherence properties limited only by the laser and ground-state spin-coherence, this measurement will also yield accurate determination of the Overhauser field narrowing induced by resonant laser dragging. 4.1.1 QD nanowires in a superconducting transmission line resonator (Ensslin/Wallraff) In an effort to integrate semiconductor quantum dots with superconducting elements in the circuit QED architecture at ETHZ a novel hybrid semiconductor/superconductor system has been realized. In a first step the coupling of a large number of photons in a transmission line resonator to a quantum dot has been observed in transport measurements (APL, 2011). In a more advanced experiment on a second generation device the coupling strength of the microwave photon to a double dot charge transition has been characterized (PRL, January 2012) and used to investigate in detail the charge stability diagram of these structures. 4.2 NV centers in a superconducting transmission line resonator, and coupled to transmon qubits. Work on this task has been entirely carried out at CEA Saclay. 4.3.1 QD-nanocavity interfaces (Imamoglu) We have shifted our focus from photonic crystal cavities to fiber-DBR (Distributed Bragg Reflector) cavities. The principal motivation here is the fact that the quality-factor of these cavities could be an order of magnitude larger and that they are perfectly tunable. Instead of restricting our capability to dots which happen to be at the cavity field maximum, we simply tune the position of the cavity by scanning the sample; nano-positioning allows us to ensure that not only is the dot we want to study is at the anti-node of the cavity field but also that the cavity can easily be tuned across the resonance. 5.2 Photonics (Imamoglu) At ETHZ the entanglement between a single QD spin and a photon generated in resonant light scattering is to be demonstrated with a single InGaAs QD in Voigt geometry. In a first experiment (classical) correlations between the spin and emitted photon energy in the computational basis have been verified and experiments on the demonstration of entanglement by observing correlations are in progress. 5.2.3 Coherent preparation of hole spin state Cancelled (Y2 review)

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References: 1. Characterization of a microwave frequency resonator via a nearby quantum dot, T. Frey, P. J.

Leek, M. Beck, K. Ensslin, A. Wallraff, and T. Ihn, Appl. Phys. Lett. 98, 262105 (2011) 2. Implementation of a Toffoli gate with superconducting circuits, A. Fedorov, L. Steffen, M. Baur, M.

P. da Silva, and A. Wallraff, Nature 481, 170–172 (2012) 3. Benchmarking a Quantum Teleportation Protocol in Superconducting Circuits Using

Tomography and an Entanglement Witness, M. Baur, A. Fedorov, L. Steffen, S. Filipp, M. P. da Silva, and A. Wallraff, Phys. Rev. Lett. 108, 040502 (2012)

4. Dipole coupling of a double quantum dot to a microwave resonator, T. Frey, P. J. Leek, M. Beck, A. Blais, T. Ihn, K. Ensslin, and A. Wallraff, Phys. Rev. Lett. 108, 046807 (2012)

5. Localization of Toric Code Defects, C. Stark, L. Pollet, A. Imamoglu and R. Renner, Phys. Rev. Lett. 107, 030504 (2011)

6. Hyperfine Interaction-Dominated Dynamics of Nuclear Spins in Self-Assembled InGaAs Quantum Dots, C. Latta, A. Srivastava & A. Imamoglu, Phys. Rev. Lett. 107, 167401 (2011)

7. Laser cooling and real-time measurement of the nuclear spin environment of a solid-state qubit, E. Togan, Y. Chu, A. Imamoglu and M. D. Lukin, Nature 478, 497 (2011)

8. Strongly correlated photons on a chip, A. Reinhard, T. Volz, M. Winger, A. Badolato, K. J. Hennessy, E. L. Hu and A. Imamoglu, Nature Photonics 6, 93 (2012)

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III .3.5. Summary of the work performed at KIT during M13-M24 1.1.2 Quantum registers with phase and flux qubits Scalable on-chip architecture for phase qubits (Ustinov) and Tunable flux qubits coupled via a resonator (Ustinov) In a joint effort with IPHT, we developed a scheme that allows one to read out a large number of qubits via a single transmission line. In this approach, each qubit is coupled dispersively to dedicated coplanar waveguide resonators. Their qubit-state dependent resonance frequencies are detected via a common microwave bus. We successfully tested this technique [16] on a chip fabricated at IPHT, which contained 7 (uncoupled) flux qubits and demonstrated their simultaneous readout. Each qubit was verified in functionality by microwave spectroscopy. Moreover, by synthesizing multi-tone driving signals, we were able to simultaneously manipulate the states of 4 qubits [17]. Calculations of the expected crosstalk of this readout system show that it should be scalable to up to 100 qubits per GHz of detection bandwidth. Furthermore, we designed a first sample were the multiplexed readout scheme is combined with qubits that are coupled by a dedicated high-Q resonator in order to realize multi-qubit logic operations. The multiplexed readout scheme is readily applicable also to phase qubits. To this end, we investigated an approach in which the transmission line resonator was replaced by a lumped element tank circuit consisting of a capacitively shunted DC-SQUID [Appl. Phys. Lett. 97, 262508 (2010)]. Its advantages are a smaller footprint and high flux resolution, which can be boosted further by operating the SQUID in the nonlinear (bifurcation) regime, reducing the required readout time. 1.3.1 Minimization of dielectric losses (Ustinov) KIT(E) has investigated dielectric losses from two-level tunneling systems in the volume of a-SiO thin films at mK temperatures and low powers [18].

See D1 and D5. 1.3.2 Microscopic models of decoherence sources (Schön/Shirman) Dissipation in superconducting qubits: We have investigated quasiparticle tunneling in a Cooper-pair box embedded in a superconducting ring to allow control of the total phase difference across the island. See Ref. [1] and D1.

We have studied decoherence in superconducting qubits due to quasiparticle tunneling which is enhanced by two known deviations from the equilibrium BCS theory. See Ref. [2] and D1.

Furthermore we have studied the use of a pair of qubits as a decoherence probe of a non-trivial environment. This dual-probe configuration is modeled by three two-level-systems which are coupled in a chain in which the middle system represents an environmental two-level-system (TLS). This TLS resides within the environment of the qubits and therefore its coupling to perturbing fluctuations (i.e. its decoherence) is assumed much stronger than the decoherence acting on the probe qubits. We study the evolution of such a tripartite system including the appearance of a decoherence-free state (dark state) and non-Markovian behavior. We find that all parameters of this TLS can be obtained from measurements of one of the probe qubits. Furthermore we show the advantages of two qubits in probing environments and the new dynamics imposed by a TLS which couples to two qubits at once. See Ref. [3] and D1.

Dephasing due to 1/f flux noise: For many types of superconducting qubits, magnetic flux noise is a source of pure dephasing. In collaboration with the experimental group of John Clarke (UC Berkeley) we have evaluated the dependence of the Ramsey and echo pure dephasing times on the form of the measured noise spectrum [S. M. Anton et al., Pure dephasing in flux qubits due to flux noise with spectral density scaling as 1/f α, arXiv:1111.7272]. These predictions should allow characterizing the flux noise and its microscopic origin from the dephasing data of the qubits. In addition we are currently working on the microscopic theory of the flux noise.

This work was performed and supported within an iARPA collaboration.

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2.1.3 Novel control techniques (Schön/Shirman) This work was performed within the EU FP7 GEOMDISS project. [I. Kamleitner, P. Solinas, C. Müller, A. Shnirman, M. Möttönen, Geometric quantum gates with superconducting qubits, Phys. Rev. B 83, 214518 (2011), DOI: 10.1103/PhysRevB.83.214518.] 2.3.2. Slowing down the nuclear spin dynamics (Schön/Shirman) No work done during Y2. 2.3.3 Controlling other noise sources (Schön/Shirman) No work done during Y2. 3.2.3 Investigation of decoherence sources in NV centers (Schön/Shirman) No work done during Y2. 4.1.1 QD nanowires in a superconducting transmission line resonator (Schön/Shirman) KIT(T) has investigated the lasing phenomenon that can occur in a double quantum-dot system coherently coupled to an electromagnetic resonator [11,12]. See D4. 4.1.2 Direct superconducting qubit - spin interface (Chalmers(T), Schön/Shirman) Finished, Y1. 4.5 Quantum communication Communication betwen qubits via cavities. (Schön/Shnirman) We proposed [5] a mechanism for coupling spin qubits formed in double quantum dots to a superconducting transmission line resonator. Coupling the resonator to the gate controlling the interdot tunneling creates a strong spin qubit–resonator interaction with strength of tens of MHz. This mechanism allows operating the system at a point of degeneracy where dephasing is minimized. The transmission line can serve as a shuttle allowing for two-qubit operations, including fast generation of qubit-qubit entanglement and the implementation of a controlled-phase gate. See D4. 5.3 Materials science 5.3.1 Improving coherence times of qubits (Ustinov) Fabrication of improved quality submicron Nb/Al-AlOx/Nb Josephson junctions: In a collaboration with the Institute for Micro- and Nanoelectrical Systems and the Institute of Solid-State Physics, both at KIT, we have developed a combined photolithography and e-beam fabrication process to fabricate high quality sub-µm sized Nb/Al-AlOx/Nb Josephson junctions [4]. See D5.3.1 5.3.3 Minimization of dielectric losses (KIT(E)) Probing the TLS Density of States in Thin a-SiO Films using Superconducting Lumped Element Resonators See 1.3.1 [Skacel et al.]. 5.3.4 Quantum manipulation of individual two-level fluctuators in Josephson qubits (KIT(E)) Generation of three-partite entanglement: In an approach to study entanglement in a hybrid system, we did experiments on a three-qubit system consisting of two TLSs strongly coupled to a phase qubit [6]. The phase qubit was used as a quantum shuttle by subsequently tuning it into resonance with different TLSs. In this way, a fully entangled tripartite state could be generated as verified by an encompassing theoretical treatment. See D4. Tuning TLSs by mechanical strain: In a novel experiment [19], we showed that the properties of two-level systems can be manipulated by mechanical strain applied to their housing material. See D5.

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5.3.5 Theoretical investigation of two-level fluctuators as quantum resource (KIT(T)) Entanglement: The KIT experimentalists demonstrated induced coherent interaction between two intrinsic two-level states (TLSs) formed by atomic-scale defects in a solid via a superconducting phase qubit. The tunable superconducting circuit serves as a shuttle communicating quantum information between the two microscopic TLSs. In collaboration with them we performed a detailed comparison between experiment and theory and find excellent agreement over a wide range of parameters [6]. We then use the theoretical model to study the creation and movement of entanglement between the three components of the quantum system. 5.4 Dynamic and/or algorithmic control of entanglement and other properties of small quantum systems Lasing and cooling (KIT(T) Circuit QED with Josephson qubits: Motivated by recent “circuit QED” experiments we studied the lasing transition and spectral properties of single-qubit lasers. We have shown that the circuit can exhibit the effect of "lasing without inversion" [7,8]. We also studied a superconducting single-electron transistor (SSET), which is coupled to a LC oscillator via the phase difference across one of the Josephson junctions [9]. This leads to a strongly anharmonic coupling between the SSET and the oscillator. The coupling can oscillate with the number of photons, which makes this system very similar to the single-atom injection maser. The advantage of a design based on superconducting circuits is the strong coupling and existence of standard methods to measure the radiation field in the oscillator. This makes it possible to study many effects that have been predicted for the single-atom injection maser in a circuit quantum electrodynamics setup. See D4 and D5. In collaboration with experimentalists at NEC, Japan we have investigated charge transport in ultrasmall superconducting single and double Josephson junctions coupled to resonant modes of the electromagnetic environment [10]. We observe pronounced current peaks in the transport characteristics of both types of devices and attribute them to the process involving simultaneous tunneling of Cooper pairs and photon emission into the resonant modes. The experimental data are well reproduced by our theoretical models.

Circuit QED with quantum dots: We studied a double quantum-dot system coherently coupled to an electromagnetic resonator [11,12,13]. A current through the dot system can create a population inversion in the dot levels and, within a narrow resonance window, a lasing state in the resonator. The lasing state correlates with the transport properties. Our results demonstrate how to interpret spectra obtained from dissipative quantum systems and specify what information is contained therein.

Parametrically modulated oscillator: We showed that the noise spectrum of a parametrically excited nonlinear oscillator can display a fine structure [14,15]. It emerges from the interplay of the nonequidistance of the oscillator quasienergy levels and quantum heating that accompanies relaxation. The heating leads to a finite-width distribution over the quasienergy, or Floquet states, even for zero temperature of the thermal reservoir coupled to the oscillator. The fine structure is due to transitions from different quasienergy levels, and thus it provides a sensitive tool for studying the distribution. For larger damping, where the fine structure is smeared out, quantum heating can be detected from the characteristic double-peak structure of the spectrum, which results from transitions accompanied by the increase or decrease of the quasienergy. WP7: Assessment of systems integration and operation See deliverable D7.

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References: 1. J. Leppäkangas, M. Marthaler, and G. Schön, Phase-dependent quasiparticle tunneling in Josephson

junctions: Measuring the cos φ term with a superconducting charge qubit, Phys. Rev. B 84, 060505(R) (2011); DOI: 10.1103/PhysRevB.84.060505

2. Juha Leppäkangas, Michael Marthaler, Fragility of multi-junction flux qubits against quasiparticle tunneling, arXiv:1109.2941v1.

3. Dual-probe decoherence microscopy: Probing pockets of coherence in a decohering environment. Jan Jeske, Jared H. Cole, Clemens Müller, Michael Marthaler, Gerd Schön; arXiv:1110.1945

4. Ch. Kaiser, J. M. Meckbach, K. S. Ilin, J. Lisenfeld, R. Schäfer, A. V. Ustinov, and M. Siegel, Aluminum hard mask technique fort the fabrication of high quality submicron Nb/Al-AlOx/Nb Josephson junctions, Supercond. Sci. Technol. 24, 035005 (2011). DOI:10.1088/0953-2048/24/3/035005

5. Pei-Qing Jin, Michael Marthaler, Alexander Shnirman, Gerd Schön, Strong coupling of spin qubits to a transmission line resonator, arXiv:1112.0869.

6. G. J. Grabovskij, P. Bushev, J. H. Cole, C. Müller, J. Lisenfeld, A. Lukashenko, A. V. Ustinov, Entangling microscopic defects via a macroscopic quantum shuttle, New J. Phys. 13, 063015 (2011); DOI: 10.1088/1367-2630/13/6/063015

7. M. Marthaler, Y. Utsumi, D. S. Golubev, A. Shnirman, and G. Schön, Lasing without Inversion in Circuit Quantum Electrodynamics, Phys. Rev. Lett. 107, 093901 (2011).

8. M. Marthaler, P. Q. Jin, J. Leppäkangas, and G. Schön, Sub-Poissonian photon statistics in a strongly coupled single-qubit laser, to be published in Journal of Physics: Conference Series, Proceeding LT26, Beijing 2011

9. M. Marthaler, J. Leppäkangas, and J. H. Cole, Lasing, trapping states, and multistability in a circuit quantum electrodynamical analog of a single-atom injection maser, Phys. Rev. B 83, 180505(R) (2011); DOI: 10.1103/PhysRevB.83.180505

10. Yu. A. Pashkin, H. Im, J. Leppäkangas, T. F. Li, O. Astafiev, A. A. Abdumalikov, E. Thuneberg, and J. S. Tsai, Charge transport through ultrasmall single and double Josephson junctions coupled to resonant modes of the electromagnetic environment, Phys. Rev. B 83, 020502(R) (2011); DOI: 10.1103/PhysRevB.83.020502

11. P. Q. Jin, M. Marthaler, J. H. Cole, A. Shnirman, G. Schön, Lasing and transport in a quantum-dot resonator circuit, Phys. Rev. B 84, 035322 (2011); DOI: 10.1103/PhysRevB.84.035322

12. P. Q. Jin, M. Marthaler, J. H. Cole, M. Köpke, J. Weis, A. Shnirman, and G. Schön, Correlation between lasing and transport properties in a quantum dot-resonator system, to be published in Journal of Physics: Conference Series, Proceeding LT26, Beijing 2011; arXiv:1109.1166

13. M. Knap, E. Arrigoni, W. von der Linden, J. H. Cole, Emission characteristics of laser-driven dissipative coupled-cavity systems, Phys. Rev. A 83, 023821 (2011); DOI: 10.1103/PhysRevA.83.023821

14. M. I. Dykman, M. Marthaler, V. Peano, Quantum heating of a parametrically modulated oscillator: Spectral signatures, Phys. Rev. A 83, 052115 (2011); DOI: 10.1103/PhysRevA.83.052115

15. L. Guo, M. Marthaler, S. André, and G. Schön, The role of damping for the driven anharmonic quantum oscillator, to be published in Journal of Physics: Conference Series, Proceeding LT26, Beijing 2011

16. M. Jerger, S. Poletto, P. Macha, U. Hübner, A. Lukashenko, E. Il'ichev and A. V. Ustinov, Readout of a Qubit Array via a Single Transmission Line, Europhys. Lett. 96, 40012 (2011). DOI:10.1209/0295-5075/96/40012

17. M. Jerger, S. Poletto, P. Macha, U. Hübner, A. Lukashenko, E. Il'ichev and A. V. Ustinov, in preparation (2012)

18. S. T. Skacel, Ch. Kaiser, S. Wu ̈nsch, H. Rotzinger, A. Lukashenko, M. Jerger, G. Weiss, M. Siegel, and A. V. Ustinov, “Probing the TLS Density of States in Thin a-SiO Films using Superconducting Lumped Element Resonators”, to be published (2012).

19. G. Grabovskij, T. Peichl, J. Lisenfeld, G. Weiss, and A. V. Ustinov, Strain Tuning of Individual Atomic Tunneling Systems Detected by a Superconducting Qubit, submitted. (2011)

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III .3.6. Summary of the work performed at IPHT during M13-M24 1.1.2 Quantum registers with phase and flux qubits (KIT, CNRS, IPHT) Tunable flux qubits coupled via a resonator: In collaboration with KIT(E), we have demonstrated a frequency multiplexing readout scheme that allows overcoming the problem of scalability. The system we designed consists of several coplanar waveguide resonators with distinct resonance frequencies. All resonators are capacitively coupled to a common transmission line, and every resonator is coupled to an individual qubit. The qubits can be read out simultaneously by applying a multitone signal to the transmission line that probes all resonators [4]. We also implemented simultaneous readout and manipulation of the qubits with the same chip layout with a detection bandwidth of 1 GHz [5]. 5.1.4 Josephson Metamaterials First measurements with a coplanar waveguide resonator coupled to 20 flux qubits are done. This work is in progress. 5.3 Materials science 5.3.1 Improving coherence times of qubits

IPHT: By making use of a transmission electron microscopy, a detailed study of the microstructure of submicron Al/Al-O/Al Josephson junction, fabricated by the conventional shadow evaporation technique, has been performed. We have demonstrated that the flatness and thickness of aluminum oxide layer strongly depends on its grain structure. The most pronounced thickness deviations are observed in the vicinity of so-called ”triple points”, where the grain boundary crosses interlayer, forming two-grain contact. Additionally we show that even for the single-grain contact, the Al/Al-O interface is not atomically flat, which can cause additional flicker noise at sub-kelvin temperatures [1]. In order to achieve better measurement sensitivity and decrease measurement induce decoherence, we have developed an ultra-low-noise SiGe heterojunction bipolar transistor amplifier. A noise temperature TN ≈ 1.4 K was measured at an ambient temperature of 4.2 K at frequencies between 100 kHz and 100 MHz for a source resistance of ∼50 Ω. The voltage gain of the amplifier was 25 dB at a power consumption of 720 μW. The input voltage noise spectral density of the amplifier is about 35 pV/√Hz. The low noise resistance and power consumption makes the amplifier suitable for readout of DC SQUID amplifiers [2]. 5.4 Dynamic and/or algorithmic control of entanglement and other properties of small quantum systems Lasing and cooling

We observed an amplification of a probe signal, passing the resonator at the frequency of its fundamental mode, by a flux qubit strongly driven by a coherent field at the frequency of another resonator mode. We have analyzed the experimental results and demonstrated that observed effects can be properly described by the dressed-state model [3]. References: [1] V. V. Roddatis, U. Hübner, B. I. Ivanov, E. Il’ichev, H.-G. Meyer, M. V. Koval’chuk, and A. L. Vasiliev J. Appl. Phys. 110, 123903 (2011)

[2] B. I. Ivanov, M. Trgala, M. Grajcar, E. Il’ichev, and H.-G. Meyer, Rev., Sci., Instr., 82, 104705 (2011).

[3] G. Oelsner, P. Macha, E. Il'ichev, U. Huebner, H.-G. Meyer, M. Grajcar, O. Astafiev in preparation.

[4] M. Jerger, S. Poletto, P. Macha, U. Hübner, A. Lukashenko, E. Il'ichev and A. V. Ustinov, Europhys. Lett. (2011)

[5] M. Jerger, S. Poletto, P. Macha, U. Hübner, A. Lukashenko, E. Il’ichev and A. V. Ustinov, in preparation (2011)

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III .3.7. Summary of the work performed at CNRS during M13-M24 This past years has corresponded to the Florent Lecocq PhD presentation and the starting of Etienne Dumur PhD. In addition Alexey Feofanov from Karlshrue joined our team as a Post-doc. We have concluded experiments with superconducting artificial atom with two degrees of freedom and started new experiments to realize QND measurements by coupling these artificial atoms with a microwave cavity. 1.1 Design, fabrication and characterisation of quantum registers with Josephson junction-based qubits Novel junction fabrication by shadow evaporation without a suspended bridge [1]: We develop a novel shadow evaporation technique for the realization of junctions and capacitors. The design by e-beam lithography of strongly asymmetric undercuts on a bilayer resist enables in situ fabrication of junctions and capacitors without the use of the well-known suspended bridge (Dolan 1977 Appl. Phys. Lett. 31 337–9). The absence of bridges increases the mechanical robustness of the resist mask as well as the accessible range of the junction size, from 10−2 μm2 to more than 104 μm2. We have fabricated Al/AlOx/Al Josephson junctions, phase qubit and capacitors using a 100 kV e-beam writer. Although this high voltage enables a precise control of the undercut, implementation using a conventional 20 kV e-beam is also discussed. The phase qubit coherence times, extracted from spectroscopy resonance width, Rabi and Ramsey oscillation decays and energy relaxation measurements, are longer than the ones obtained in our previous samples realized by standard techniques. These results demonstrate the high quality of the junction obtained by this bridge-free technique. Nonlinear Coupling between the Two Oscillation Modes of a dc SQUID [2]: We make a detailed theoretical description of the two-dimensional nature of a dc SQUID, analyzing the coupling between its two orthogonal phase oscillation modes. While it has been shown that the mode defined as ‘‘longitudinal’’ can be initialized, manipulated, and measured, so as to encode a quantum bit of information, the mode defined as ‘‘transverse’’ is usually repelled at high frequency and does not interfere in the dynamics. We show that, using typical parameters of existing devices, the transverse mode energy can be made of the order of the longitudinal one. In this regime, we can observe a strong coupling between these modes, described by a Hamiltonian providing a wide range of interesting effects, such as conditional quantum operations and entanglement. This coupling also creates an atomic-like structure for the combined two mode states, with a V-like scheme. Coherent frequency conversion in a superconducting artificial atom with two internal degrees of freedom [3]: By adding a large inductance in a dc-SQUID phase qubit loop, one decouples the junctions’ dynamics and creates a superconducting artificial atom with two internal degrees of freedom. In addition to the usual symmetric plasma mode (s-mode) which gives rise to the phase qubit, an anti-symmetric mode (a-mode) appears. These two modes can be described by two anharmonic oscillators with eigenstates |ns> and |na> for the s and a-mode, respectively. We show that a strong nonlinear coupling between the modes leads to a large energy splitting between states |0s, 1a> and |2s, 0a>. Finally, coherent frequency conversion is observed via free oscillations between the states |0s, 1a> and |2s, 0a>. New development during this last year: A new experimental set-up is currently developed to realize QND measurements using a two degree of freedom artificial atom coupled to coplanar waveguide cavity. To realize this aim we have performed theoretical analysis and numerical simulation and optimization of the superconducting circuits. We started fabrication of the samples and wiring of the new dilution to realize QND measurements. 5.3 Materials science 5.3.2 Epitaxial superconducting and tunnel barrier layers for high Q resonator and phase qubits (CNRS) See WP1. References:

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[1] Junction fabrication by shadow evaporation without a suspended bridge, F. Lecco, I. M Pop, Z. Peng, I. Matei, T. Crozes, T. Fournier, C. Naud, W. Guichard and O. Buisson, Nanotechnology 22 315302 (2011).

[2] Non-linear coupling between the two oscillation modes of a dc-SQUID, F. Lecocq, J. Claudon, O. Buisson, and P. Milman, Phys. Rev. Lett. 107, 197002 (2011).

[3] Superconducting artificial atom with two internal degrees of freedom, F. Lecocq, I. M. Pop, I. Matei, E. Dumur, A. Feofanov, C. Naud, W. Guichard, O. Buisson, Phys. Rev. Lett. 108, (2012)

[4] Asymmetric Cooper pair transistor in parallel to a dc SQUID: Two coupled quantum systems, A. Fay, W. Guichard, O. Buisson, and F. W. J. Hekking, Phys. Rev. B 83, 184510 (2011)

[5] Etching suspended superconducting hybrid junctions from a multilayer, H. Q. Nguyen, L. M. A. Pascal, Z. H. Peng, O. Buisson , B. Gilles, C. Winkelmann , H. Courtois. Submitted for publication. arXiv:1111.3541.

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III .3.8. Summary of the work performed UNIBAS during M13-M24 2.3 Control of decoherence 2.3.2. Slowing down the nuclear spin dynamics (Loss)

We analyzed the ordered state of nuclear spins embedded in an interacting two-dimensional electron gas (2DEG) with Rashba spin-orbit interaction (SOI). Stability of the ferromagnetic nuclear-spin phase is governed by nonanalytic dependences of the electron spin susceptibility on the momentum q and on the SOI coupling constan. Renormalization in the Cooper channel is capable of reversing the sign of the q-dependence of the spin susceptibility and thus stabilizing the ordered state. We also show that a combination of the electron-electron and SO interactions leads to a new effect: long-wavelength Friedel oscillations in the spin (but not charge) electron density induced by local magnetic moments [1].

We extended the Mermin-Wagner theorem to a system of lattice spins which are spin coupled to itinerant and interacting charge carriers. We used the Bogoliubov inequality to rigorously prove that neither (anti-) ferromagnetic nor helical long-range order is possible in one and two dimensions at any finite temperature. Our proof applies to a wide class of models including any form of electron-electron and single-electron interactions that are independent of spin. In the presence of Rashba or Dresselhaus spin-orbit interactions (SOI) magnetic order is not excluded and intimately connected to equilibrium spin currents. However, in the special case when Rashba and Dresselhaus SOIs are tuned to be equal, magnetic order is excluded again. This opens up a new possibility to control magnetism electrically [2]. 2.3.3 Controlling other noise sources (Loss) We analyzed the low-energy spectrum of a two-electron double quantum dot under a potential bias in the presence of an external magnetic field. We focus on the regime of spin blockade, taking into account the spin orbit interaction and hyperfine coupling of electron and nuclear spins. Starting from a model for two interacting electrons in a double dot, we derived a perturbative, effective two-level Hamiltonian in the vicinity of an avoided crossing between singlet and triplet levels, which are coupled by the spin-orbit and hyperfine interactions. We evaluated the level splitting at the anticrossing, and show that it depends on a variety of parameters including the spin orbit coupling strength, the orientation of the external magnetic field relative to an internal spin-orbit axis, the potential detuning of the dots, and the difference between hyperfine fields in the two dots. We provided a formula for the splitting in terms of the spin orbit length, the hyperfine fields in the two dots, and the double dot parameters such as tunnel coupling and Coulomb energy. This formula should prove useful for extracting spin orbit parameters from transport or charge sensing experiments in such systems. We identify a parameter regime where the spin orbit and hyperfine terms can become of comparable strength, and discuss how this regime might be reached [3].

4.1 Superconducting-semiconducting hybrid devices Crossed Andreev Reflection in Quantum Wires (Loss): We theoretically study tunneling of Cooper pairs from an s-wave superconductor into two semiconductor quantum wires with strong spin-orbit interaction under magnetic field, which approximate helical Luttinger liquids. The entanglement of electrons within a Cooper pair can be detected by the electric current cross correlations in the wires. By controlling the relative orientation of the wires, either lithographically or mechanically, on the substrate, the current correlations can be tuned, as dictated by the initial spin entanglement. This proposal of a spin-to-charge readout of quantum correlations is alternative to a recently proposed utilization of the quantum spin Hall insulator [4].

Modulated finite quantum wires and rings (Loss): We study finite quantum wires and rings in the presence of a charge density wave gap induced by a periodic modulation of the chemical potential. We show that the Tamm-Shockley bound states emerging at the ends of the wire are stable against weak disorder and interactions, for discrete open chains and for continuum systems. The low-energy physics can be mapped onto the Jackiw-Rebbi equations describing massive Dirac fermions and bound end states. We treat interactions via the continuum model and show that they increase the charge gap and further localize the end states. In an Aharonov-Bohm ring with weak link, the bound states give rise to an unusual 4\pi-periodicity in the spectrum and persistent current as function of an external flux. The electrons placed in the two localized states on the opposite ends of the wire can interact via exchange interactions and this setup can be used as a

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double quantum dot hosting spin-qubits [6].

4.1.1 QD nanowires in a superconducting transmission line resonator See D4 4.4 Long lived quantum information storage in nuclear spin ensembles 4.4.2 Fully Polarized Nuclear Spin Ensemble for Long Lived Quantum Information Storage (Zumbühl) The important issue addressed by UNIBAS(E) was to cool samples down to ultra-low, sub-mK temperatures, with the goal of achieving full thermodynamic nuclear polarization. Excellent progress was achieved during Y2, with a network of 21 parallel nuclear refrigerators (NRs) cooling down to 185 μK, and with test experiments on Coulomb blockade [L. Casparis, M. Meschke, D. Maradan, A. C. Clark, C. Scheller, K. K. Schwarzwalder, J. P. Pekola, D. M. Zumbuhl, Arxiv:1111.1972.]. See D4. 4.5 Quantum Communication The electron spin is a natural two level system that allows a qubit to be encoded. When localized in a gate defined quantum dot, the electron spin provides a promising platform for a future functional quantum computer. The essential ingredient of any quantum computer is entanglement---between electron spin qubits---commonly achieved via the exchange interaction. Nevertheless, there is an immense challenge as to how to scale the system up to include many qubits. Here we propose a novel architecture of a large scale quantum computer based on a realization of long-distance quantum gates between electron spins localized in quantum dots. The crucial ingredients of such a long-distance coupling are floating metallic gates that mediate electrostatic coupling over large distances. We show, both analytically and numerically, that distant electron spins in an array of quantum dots can be coupled selectively, with coupling strengths that are larger than the electron spin decay and with switching times on the order of nanoseconds [5].

5.4 Dynamic and/or algorithmic control of entanglement and other properties of small quantum systems Kitaev honeycomb model (Loss) We investigate the exact solution of the honeycomb model proposed by Kitaev and derive an explicit formula for the projector onto the physical subspace. The physical states are simply characterized by the parity of the total occupation of the fermionic eigenmodes. We consider a general lattice on a torus and show that the physical fermion parity depends in a nontrivial way on the vortex configuration and the choice of boundary conditions. In the vortex-free case with a constant gauge field we are able to obtain an analytical expression of the parity. For a general configuration of the gauge field the parity can be easily evaluated numerically, which allows the exact diagonalization of large spin models. We consider physically relevant quantities, as in particular the vortex energies, and show that their true value and associated states can be substantially different from the one calculated in the unprojected space, even in the thermodynamic limit [7]. Universal gates with anisotropic spin chains (Loss) We have shown that anisotropic spin chains with gapped bulk excitations and magnetically ordered ground states offer a promising platform for quantum computation, which bridges the conventional single-spin-based qubit concept with recently developed topological Majorana-based proposals. We show how to realize the single-qubit Hadamard, phase, and \pi/8 gates as well as the two-qubit controlled-not (cnot) gate, which together form a fault-tolerant universal set of quantum gates. The gates are implemented by judiciously controlling Ising exchange and magnetic fields along a network of spin chains, with each individual qubit furnished by a spin-chain segment. A subset of single-qubit operations is geometric in nature, relying on control of anisotropy of spin interactions rather than their strength. We contrast topological aspects of the anisotropic spin-chain networks to those of p-wave superconducting wires discussed in the literature [8].

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Exploration of pulse shaping and optimal control (Bruder): In collaboration with the ETHZ (Wallraff) group, the UNIBAS(T) (Bruder) group studied the efficient realization of a Toffoli gate with superconducting qubits in a circuit-QED setup using quantum-control methods [9]. Protocol to generate a Greenberger- Horne-Zeilinger (GHZ) state (Bruder): We have proposed a circuit quantum electrodynamics (QED) realization of a protocol to generate a Greenberger- Horne-Zeilinger (GHZ) state for N superconducting transmon qubits homogeneously coupled to a superconducting transmission line resonator in the dispersive limit. We derive an effective Hamiltonian with pairwise qubit exchange interactions of the XY type, that can be globally controlled. Starting from a separable initial state, these interactions allow us to generate a multi-qubit GHZ state. We discuss how to probe the nonlocal nature and the genuine N-partite entanglement of the generated state [10]. References: [1] R.A. Zak, D.L. Maslov, and D. Loss, Ferromagnetic order of nuclear spins coupled to conduction electrons: a combined effect of the electron-electron and spin-orbit interactions, arXiv:1112.4786

[2] D. Loss, F.L. Pedrocchi, and A.J. Leggett, Absence of spontaneous magnetic order of lattice spins coupled to itinerant interacting electrons in one and two dimensions, Phys. Rev. Lett. 107, 107201 (2011); arXiv:1107.1223

[3] D. Stepanenko, M. Rudner, B.I. Halperin, and D. Loss, Singlet-triplet splitting in double quantum dots due to spin orbit and hyperfine interactions, arXiv:1112.1644 (submitted to PRB)

[4] K. Sato, D. Loss, and Y. Tserkovnyak, Crossed Andreev Reflection in Quantum Wires with Strong Spin-Orbit Interaction, arXiv:1109.6357. [5] L. Trifunovic, O. Dial, M. Trif, J.R. Wootton, R. Abebe, A. Yacoby, and D. Loss, Long-distance spin-spin coupling via floating gates, Phys. Rev. X 2, 011006 (2012); arXiv:1110.1342. [6] S. Gangadharaiah, L. Trifunovic, and D. Loss, Localized end states in density modulated quantum wires and rings, arXiv:1111.5273 (accepted for publication in PRL). [7] F.L. Pedrocchi, S. Chesi, and D. Loss, Physical solutions of the Kitaev honeycomb model, Phys. Rev. B 84, 165414 (2011); arXiv:1105.4573 [8] Y. Tserkovnyak and D. Loss, Universal quantum computation with topological spin-chain networks, Phys. Rev. A 84, 032333 (2011); arXiv:1104.1210 [9] V.M. Stojanovic, A. Fedorov, A. Wallraff, and C. Bruder, Quantum-control approach to realising a Toffoli gate in circuit QED; arXiv:1108.3442 , accepted in Phys. Rev. B [10] S. Aldana, Y.-D. Wang, and C. Bruder, Greenberger-Horne-Zeilinger generation protocol for N superconducting transmon qubits capacitively coupled to a quantum bus, Phys. Rev. B 84, 134519 (2011). DOI: 10.1103/PhysRevB.84.134519

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III .3.9. Summary of the work performed at TUM during M13-M24 2.1 Integrated universal spin qubit functionality in semiconductor quantum dots 2.1.2 Self-assembled quantum dots (Finley) Following on from our work on the optical preparation and readout of electron spin in self-assembled QD-nanostructures, performed during M1-12, in the second reporting period the TUM team worked in several directions: (i) The development of growth recipes for self-assembled quantum dots with electrically tunable g-factors [V. Jovanov, et al. Phys. Rev. B 83, 161303 (2011)], (ii) The observation of metastable hot Trions in the emission spectrum of individual dots and their use to perform spin readout with improved signal-noise ratio [V. Jovanov, et al, Phys. Rev. B 84, 235321 (2011)], (iii) The observation of excited state quantum couplings and a conditional optical response for an individual QD-molecule [K. Müller et al, Phys. Rev. B 84, 081302 (2011)], (iv) The use of ultrafast photocurrent to measure the exciton-phonon spectrum of inelastic interdot tunneling in a single QD-molecule [K. Müller et al, arXiv 1111.3137 – PRL accepted (2012)] and (v) Measurement of the coherent precession of a single hole in an individual QD-molecule [K. Müller et al – in preparation]. Since the majority of these studies were published in the references given above, we summarize in this report only (iv) and (v) to document the most recent advances. Over the second reporting period we developed an ultrafast photocurrent pump-probe technique that allows us to use picosecond optical pulses to prepare single charge carriers, directly probe their dynamics and measure their spin projection. We started by employing these techniques to directly monitor electron tunneling between discrete orbital states in a pair of spatially separated quantum dots. Immediately after excitation, several peaks are observed in the pump-probe photocurrent spectrum due to Coulomb interactions between the photo-generated charge carriers. By tuning the relative energy of the orbital states in the two dots and monitoring the temporal evolution of the pump-probe spectra the electron and hole tunneling times are separately measured and resonant tunneling between the two dots is shown to be mediated both by elastic and inelastic processes. Ultrafast (< 5 ps) inter-dot tunneling is shown to occur over a surprisingly wide bandwidth, up to 8meV, reflecting the spectrum of exciton-acoustic phonon coupling in the system.

We then continued to exploit the rapid electron tunnelling out of the QD-molecule to perform ultrahigh fidelity initialization of a single hole in the system and monitor its coherent precession in an externally applied field. Excitons with a well-defined spin projection are initialized in one of the two dots using circularly polarized picosecond pulses. The time-dependent spin configuration is probed by the spin selective optical absorption of the resulting few Fermion complexes. Taking advantage of sub-5 ps electron tunneling to an orbitally excited state of the other dot, we initialize a single hole spin with a purity of > 96 %, i.e., much higher than demonstrated in previous single dot experiments. Measurements performed with magnetic fields applied in Voigt geometry allow us to monitor the coherent Larmor precession of the single hole spin with no observable loss of spin coherence within the ~300ps hole tunneling lifetime. Thereby, the purity of the hole spin initialization remains unchanged for all investigated magnetic fields. 2.2 A scalable spin qubit technology (Finley) We also worked on site selective growth of GaAs-InGaAs nanowire (NW) heterostructures by ultra–high purity solid source MBE. This is important since these NW based nanostructures are key to the development of optically active “few-QD” nanostructures for the spin and photonic goals in WP-2 (Task 2.2, M2.1), and WP-4 (M4.2), respectively. Here, GaAs and InAs nanowires were grown without external catalyst using molecular beam epitaxy (MBE) on nano-patterned SiO2/Si templates. Site-selective growth of nanowires from pre-defined nucleation holes was achieved with an areal density as low as ~107cm-2. This facilitates optical measurements on individual NW- heterostructures with optical addressing along the NW growth axis - vital for utilizing the optical selection rules for spin-photon conversion in WP-2. From M6 onwards efforts focussed specifically on the incorporation of InxGa(1-x)As segments into GaAs nanowires to form quantum dots and optical passivation of the NW surface by growing an Al0.3Ga0.7As shell. A series of core-shell GaAs-AlGaAs NW samples [see e.g. A. Fontcuberta i Morral et al., Appl. Phys. Lett. 92, 063112 (2008), C. Colombo et al., Phys. Rev. B 77, 155326 (2008)] were grown with shell thicknesses in the range of 8-100nm. Comparison of the luminescence efficiency of these samples and an uncapped reference sample revealed enhancements in excess of >103 with respect to the uncapped NWs – essentially independent of the shell thickness. Time-resolved and temperature-dependent photoluminescence studies were performed to obtain a better understanding of the mechanisms determining the internal quantum efficiency. The TUM group

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thoroughly investigated the effect of growth temperature and III/V ratio on the nanowire growth and identified a growth regime that does not involve a catalyst particle in the formation of GaAs NWs on Si. Our findings are expected to provide a route toward abrupt axial nanowire heterostructures that are typically prevented by a catalyst particle during growth. Furthermore, the incorporation of InxGa(1-x)As segments into GaAs nanowires was successfully demonstrated. In particular the effect of growth temperature on the In incorporation was investigated. Capping of such InGaAs-GaAs heterostructure nanowires with an AlGaAs shell led to extremely bright PL emission from the InGaAs segments with intensities up to 105cps. Results of the nanowire growth studies performed during M1-M8 were presented at the 5th annual Nanowire Growth Workshop (Rome, 4-5th Nov 2010 - www.nwg2010.artov.imm.cnr.it/index.html), at the EP2DS19/MSS15 (Tallahassee, 25-29th Jul 2011 - http://www.magnet.fsu.edu/mediacenter/seminars/ep2dsmss/), at SemiconNano2011 (Traunkirchen, 11-16th Sep 2011 - http://www.hlphys.jku.at/SemiconNano2011/), at the MRS Fall Meeting (Boston, 18th Nov-2nd Dec, http://www.mrs.org/fall2011/) and contribute specifically towards deliverable D2.1. Most recently, sharp line emission has been obtained for InAs quantum dots embedded within MBE grown GaAs nanowires with linewidths as sharp as 300µeV indicative of the weak sensitivity of such nanostructures to environmental dephasing.

4.4 Long lived quantum information storage in nuclear spin ensembles 4.4.1 Efficient processing of quantum information stored in localized nuclear spin ensembles in single and coupled optically active quantum dots (QDs). (Finley) In the first reporting period, the TUM group performed QD photocurrent (PC) measurements with resonant optical excitation and observed highly efficient and asymmetric dynamic nuclear spin pumping (DNSP) in a single, charge neutral QD subject to resonant optical pumping of X0. These studies specifically address task 4.4.1. The group observed a large maximum nuclear spin polarization of 54% that was shown to be much stronger following pumping of the higher energy Zeeman state. The measurements clearly revealed strong hysteresis and a pronounced increase of the effective Zeeman energy in the case when the nuclear spin system is pumped and allowed to evolve towards an equilibrium state. Over the second reporting period, the group have extended these studies to perform time-resolved measurements that have allowed us to directly monitor the build-up of the nuclear spin polarization in real time and quantitatively study the dynamics of the DNSP process. A strong dependence of the observed dynamic nuclear polarization on the applied magnetic field was found, with resonances in the pumping efficiency being observed for particular magnetic fields. Most recently, the TUM group have extended such studies to coupled quantum dots, the aim being to probe nuclear spin diffusion in the system by inducing DNSP in one of the two dots forming the molecule whilst testing for the local Overhauser field in the other. 5.2.2 Efficient single photon emission into guided modes in a photonic crystal chip (Finley) Over the reporting period, M13-M24 the TUM group performed experimental investigations of the emission characteristics of single self-assembled In- GaAs QDs coupled to the guided mode of a linear defect (W1) photonic crystal waveguide (Laucht et al, arXiv 1201.5153 (2012) – PRX accepted). Spatially resolved photoluminescence measurements were performed to locate the position of individual QDs inside the PWG and slow light effects were used to enhance emission into the guided mode. By comparing the emission intensity and spontaneous emission dynamics detected along an axis perpendicular to the sample surface with similar measurements detected in the plane of the photonic crystal waveguide, the group could obtain strong evidence for significant enhancements of the radiative coupling to the propagating waveguide mode. Most notably, a 55±8x more efficient coupling to the PWG mode is measured compared to radiation into free space modes along the vertical detection axis. Time-resolved photoluminescence measurements detected on the same QD transition allowed the TUM group to estimate the fraction of all spontaneous emission emitted into the waveguide mode. This was shown to be very high - 85 % < β < 96 % of all radiation being emitted into the propagating mode. Second order photon autocorrelation g(2) measurements confirm the single photon character of the QD emission into the waveguide mode with a multi-photon probability of only g(2)(0) = 0.27±0:07, compared to a Poissonian source with the same average intensity. The wide bandwidth of the PWG guided modes (> 25 meV) provides a highly attractive route towards the design of on-chip quantum optics experiments obviating the need to tune the QD transition into spectral resonance with a high-Q photonic crystal cavity mode.

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References: D. Rudolph, et al., Direct observation of a non-catalytic growth regime for GaAs nanowires, Nano Letters 11, 3848 (2011)

S. Hertenberger, et al., Absence of vapor-liquid-solid growth during molecular beam epitaxy of self-induced InAs nanowires on Si, Appl. Phys. Lett. 98, 123114 (2011)

V. Jovanov, et al., Observation and explanation of strong electrically tunable exciton g factors in composition engineered In(Ga)As quantum dots, Phys. Rev. B 83, 161303 (2011)

V. Jovanov et al., Direct observation of metastable hot trions in an individual quantum dot, Phys. Rev. B 84, 235321 (2011)

K. Müller et al., Excited state quantum couplings and optical switching of an artificial molecule, Phys. Rev. B 84, 081302 (2011)

F. Klotz et al., Coplanar stripline antenna design for optically detected magnetic resonance on semiconductor quantum dots, Rev. Sci. Instrum. 82, 074707 (2011)

M. Kaniber et al, Electrical control of the exciton-biexciton splitting in self-assembled InGaAs Quantum dots, Nanotechnology 22, 325202, (2011)

A. Laucht et al., Nonresonant feeding of photonic crystal nanocavity modes by quantum dots, J. Appl .Phys. 109, 102404, (2011)

K. Müller et al., Electrical control of ultrafast intra-molecular dynamics in an artificial molecule, arXiv 1111.3137– accepted for Phys. Rev Lett. (2012)

A. Laucht, et al., A Waveguide-Coupled On-Chip Single Photon Source, arXiv 1201.5153– accepted for Phys. Rev. X (2012)

V. Jovanov et al., Highly Non-linear Excitonic Zeeman Spin-Splitting in Composition-Engineered Artificial Atoms, arXiv:1112.2585 – accepted for Phys. Rev. B (2012)

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III .3.10. Summary of the work performed at USTUTT during M13-M24 3.1 Spin qubits in NV centres in diamond 3.1.1 Generate spins qubits in isotopically engineered diamond The ability to investigate weakly coupled nuclear spins via electron spin ancillae offers great potential for novel quantum sensing applications. Nitrogen-Vacancy centers in diamond with long (several ms) spin coherence times are promising solid state systems for quantum information processing and detection at room temperature. In high magnetic fields single shot readout schemes promise sensing below the Heisenberg limit. In the project we fabricated diamond samples with a 12C isotope concentration > 99.99%. We subsequently exploit the long coherence times and dilute bath to detect weakly coupled 13C spins via the NV center. In this way we achieve T2 times ranging from 2 to 4 ms, depending on the NV, with Hahn echo measurements. This is close to the spin relaxation time T1 (~6ms) which defines the ultimate limit for T2 ≤ 2*T1. 3.1.2 Demonstrate entanglement between color centers at distances allowing individual optical addressing The challenge in entangling 2 NV center is the rather weak dipol-dipol interaction making small distances lower than 30 nm necessary. To increase the creation efficiency NV pairs were created via ion implantation using a mica nano channel mask. Using this method chances for finding NVs with a distance lower than 30 nm are about 1% per implantation spot. An NV pair with a dipolar coupling of 4.93±0.05 kHz was identified. The distance between both NV centres is around 24 nm. In order to entangle both NV centres, a Hahn echo was performed on the NV centres simultaneously. During the Hahn echo, each NV collects a phase depending on the state of the other NV. Since both NVs are in a superposition state, a phase superposition is collected. For the evolution time of τ=1/2νdipthe phase superposition can be mapped by a π/2 pulse into an entangled state. With local pulses (only affecting one NV), all possible entangled states were created. Lifetime of entangled states as well as entanglement storage was demonstrated. 3.1.3 Demonstrate state transfer between flying qubit and spin qubit One of the central opportunities of the diamond system is the possibility to use single defect centers as local nodes in a quantum repeater scheme. Those schemes put a number of requirements on the local nodes. First of all a versatile spin photon interface is necessary, which was shown to be the case for diamond NV centers. Secondly for efficient scaling of transfer probability in repeater nodes local qubits (around 4-6) are necessary for quantum state storage and entanglement purification. In the past year the Stuttgart group has worked out a scheme to for efficient quantum state transfer between an arbitrary photon state and nuclear spin qubits at the NV center. The group is currently working on its experimental implementation. In short the proposed scheme relies on generating an entangled electron nuclear spin state to be generated prior to photon absorption. Upon excitation to the A2 state, the orbital part of the wavefunction ensures polarization selection rules for σ+,- polarized light. In this case, the nuclear spin wavefunction is preserved upon excitation and emission which results in storage of an arbitrary light state in a nuclear spin wavefunction.

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References:

1. Electric-Field Sensing Using Single Diamond Spins. F. Dolde, H. Fedder, M. W. Doherty, T. Nobauer, F. Rempp, G. Balasubramanian, T. Wolf, J. Wrachtrup, et al. Nature Physics 7, no. 6 (2011): 459-63.

2. High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond L.T. Hall, J. Wrachtrup, L. Hollenberg et al., Nature Scientific Reports (accepted 7th of February 2012)

3. Quantum Measurement and Orientation Tracking of Fluorescent Nanodiamonds inside Living Cells L.P. McGuinness, Y. Yan, A. Stacey, D. A. Simpson, L. T. Hall, D. Maclaurin, S. Prawer, J. Wrachtrup, et al. Nature Nanotechnology 6, no. 6 (2011): 358-63.

4. Creation of Colour Centres in Diamond by Collimated Ion-Implantation through Nano-Channels in Mica S.Pezzagna, D. Rogalla, H. W. Becker, I. Jakobi, F. Dolde, B. Naydenov, J. Wrachtrup, et al. Physica Status Solidi a-Applications and Materials Science 208, no. 9 (2011): 2017-22.

5. Highly Efficient Fret from a Single Nitrogen-Vacancy Center in Nanodiamonds to a Single Organic Molecule J.Tisler, R. Reuter, A. Lammle, F. Jelezko, G. Balasubramanian, P. R. Hemmer, F. Reinhard, and J. Wrachtrup. Acs Nano 5, no. 10 (2011): 7893-98.

6. Dark States of Single Nitrogen-Vacancy Centers in Diamond Unraveled by Single Shot Nmr G. Waldherr, J. Beck, M. Steiner, P. Neumann, A. Gali, Th Frauenheim, F. Jelezko, and J. Wrachtrup. Physical Review Letters 106, no. 15 (2011)

7. Violation of a Temporal Bell Inequality for Single Spins in a Diamond Defect Center G. Waldherr, P. Neumann, S. F. Huelga, F. Jelezko, and J. Wrachtrup Physical Review Letters 107, no. 9 (2011)

8. High-dynamic-range magnetometry with a single nuclear spin in diamond G. Waldherr, J.Beck, P. Neumann, J. Wrachtrup et al. Nature Nanotechnology 7, 105 (2012)

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III .3.11. Summary of the work performed at SNS during M13-M24 The research of the SNS team has concentrated in the last year on the following three main activities: 1) Quantum optimal control 2) Topological and geometric computation with superconducting qubits 3) Efficient codes to simulate the dynamics of many-qubit systems. The postdoc hired on the project, Davide Rossini, started in October 2010 and will last till the end of the project. He worked mainly on WP1 and WP5.

1.3 Control of decoherence in Josephson qubits

1.3.2 Microscopic models of decoherence sources

Protected quantum computation with superconducting qubits We investigated the transport properties of a bilayer exciton condensate that is contacted by four superconducting leads. We focused on the equilibrium regime and investigate how the Josephson currents induced in the bilayer by phase biases applied to the superconducting electrodes are affected by the presence of an exciton condensate in the bulk of the system. The system we investigate provides an implementation of the supercurrent mirror proposed by Kitaev as a viable way to realize topologically protected qubits. As long as the distance between the superconducting electrodes is much larger than the exciton coherence length, the Josephson current depends only on the difference between the phase biases in the two layers. This result holds true in both short- and long-junction limits. We relate it to a novel correlated four-particle Andreev process which occurs at the superconductor - exciton condensate interface. We finally estimated the possible origins of decoherence in this setup and estimated their order of magnitudes in a possible experiment. 1.3.3 Quantum optimal control for Josephson qubits 1.3.3.1 We introduced a new approach to assess the error of control problems we aim to optimize. The method offers a strategy to define new control pulses that are not necessarily optimal but still able to yield an error not larger than some fixed a priori threshold, and therefore provide control pulses that might be more amenable for an experimental implementation. We applied this formalism to an exactly solvable model and to the Landau-Zener model, whose optimal control problem is solvable only numerically. The developed method may be of importance for applications, as solid state qubits, where a high degree of controllability of the dynamics of quantum systems is required. At the same time distortions on the applied pulses are unavoidable and therefore one is interested in estimated to which extent it is possible to tolerate such distortions without large deviations from the optimal fidelity.

1.3.3.2 We continued our work on exploring the ultimate limits of optimal control. The ability to accurately control a quantum system is a fundamental requirement in many areas of modern sciencesuch as quantum information processing. It is usually necessary to realize these quantum manipulations in the shortest possible time in order to minimize decoherence, and with a large stability against fluctuations of the control parameters. While optimizing a protocol for speed leads to a natural lower bound in the form of the quantum speed limit rooted in the Heisenberg uncertainty principle on the other side stability against parameter variations typically requires adiabatic following of the system. The SNS analyzed theoretically the optimal pulses at the quantum speed limit and collaborated with their experimental implementation with the group of Prof. Arimondo (Pisa). The experimental implementation of these optimal control schemes that achieve nearly perfect fidelity for a two-level quantum system realized with Bose-Einstein condensates in optical lattices. By suitably tailoring the time-dependence of the system's parameters, we transformed an initial quantum state into a desired final state through a short-cut protocol reaching the maximum speed compatible with the laws of quantum mechanics. We implement the recently proposed transitionless superadiabatic protocols, in which the system perfectly follows the instantaneous adiabatic ground state. We demonstrated that superadiabatic protocols are extremely robust against parameter variations, making them useful for practical applications

1.3.3.3 We studied optimized protocols for adiabatic quantum computation. We analyzed several situations including the adiabatic Grover's search algorithm. We discussed under which conditions the fidelity at the end of the computation is arbitrary close to one. Furthermore we showed that the minimum time required to enter this regime is T ~ p/D, where D is the minimum spectral gap, unveiling an intimate connection between an optimized unitary dynamics and the intrinsic measure of the Hilbert space for pure states. Surprisingly, the dynamics is non-adiabatic, this result can be understood by assuming a simple two-level dynamics for the many-body system. Furthermore we introduced an algorithm to perform an optimal adiabatic evolution that

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operates without an a priori knowledge of the system spectrum. By probing the system gap locally, the algorithm maximizes the evolution speed, thus minimizing the total evolution time. We tested the algorithm on the Landau-Zener transition and then apply it on the quantum adiabatic computation of 3-SAT: The result is compatible with an exponential speed-up for up to twenty qubits with respect to classical algorithms. 1.4 Design and implementation of protocols and algorithms that make maximal use of the available hardware 1.4.1 Geometric quantum computation with circuit-QED We proposed a method to generate environment induced geometric phase in qubit-oscillator system. In general, the problem of enforcing quantumness under unfavorable conditions, such as increasingly higher temperatures, have received great attention in the last years, being the topic of great interest both from a technological and from a fundamental point of view. In this line of thoughts, we considered a system in which genuine non-classical features not only survive to temperature and dissipation, but they are indeed induced by these environmental influences. In the spirit of previous works we considered the famous model called Von Neumann measurement scheme, which models the measurement process as a coupling between a large measurement apparatus, used as a probe, and the microscopic system on which the measurement is performed. This scheme is studied under a new prospective, using the microscopic system (a qubit) to measure a dissipation-induced geometric phase attached to the macroscopic system (an harmonic oscillator), with the roles of the two systems somehow inverted respect to Von Neumann original model. We showed how such a phase, generated by a cyclic evolution in the phase space of the harmonic oscillator, can be kicked back on the qubit, which plays the role of a quantum interferometer. The environment induced geometric phase can then be measured through an interference scheme on the qubit. In the figure below the interference fringes as detected using the qubit as a function of the displacement and the variance of an initially prepared thermal gaussian state. We further extended our study to finite-temperature dissipative Markovian dynamics. Potential implementations of the proposed scheme are circuit-QED systems or micro nano-mechanical devices coupled to an effective two-level system. 1.4.2 Charge flow in an unbiased InAs nanowire (NW) embedded in a SQUID So far, nano-scale pumps have been realised only in Coulomb blockade systems, whereas evidence for pumping in the absence of Coulomb-blockade has been elusive. It was proposed that a potentially interesting setup to experimentally detect the effect would be to use the ac Josephson effect to induce periodically time-dependent Andreev-reflection amplitudes in a hybrid normal-superconducting system. Very recently the experimental detection of charge flow in an unbiased InAs nanowire (NW) embedded in a superconducting quantum interference device (SQUID) was achieved in the NEST laboratories in Pisa. The SNS team contributed to the theoretical analysis of the experiment. In this system, pumping may occur via the cyclic modulation of the phase of the order parameter of different superconducting electrodes. The understanding and measurement of the symmetry of the current with respect to the enclosed magnetic flux and bias SQUID current was a crucial signature of pumping. Currents exceeding 20 pA were measured at 250 mK. 4.5 Quantum communication Mechanical resonators are macroscopic quantum objects with great potential. They couple to many different quantum systems such as spins, optical photons, cold atoms, and Bose Einstein condensates. It is however difficult to measure and manipulate the phonon state due to the tiny motion in the quantum regime. On the other hand, microwave resonators are powerful quantum devices since arbitrary photon state can be synthesized and measured with a quantum tomography. We showed that a linear coupling, strong and controlled with a gate voltage, between the mechanical and the microwave resonators enables to create quantum phonon states, manipulate hybrid entanglement between phonons and photons and generate entanglement between two mechanical oscillators. In circuit quantum optomechanics, the mechanical resonator acts as a quantum transducer between an auxiliary quantum system and the microwave resonator, which is used as a quantum bus. See D4. 5.4 Dynamic and/or algorithmic control of entanglement and other properties of small quantum systems Quantum control/algorithms/multi-qubit entangled states of few-qubit systems A very important problem towards the understanding of many-qubit system is the ability to efficiently simulate its quantum dynamics.

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In recent years, starting from the celebrated density matri renormalization group algorithm, a number of methods have been propsed. We recently developed a number of codes that allow to study the low lying spectrum and the quantum dynamics of interacting qubits and we applied to several models in one-dimension with periodic boundary conditions. We also introduced an algorithm to perform an optimal adiabatic evolution that operates without an apriori knowledge of the system spectrum. By probing the system gap locally, the algorithm maximizes the evolution speed, thus minimizing the total evolution time. We tested the algorithm on the Landau-Zener transition and then apply it on the quantum adiabatic computation of 3-SAT: The result is compatible with an exponential speed-up for up to twenty qubits with respect to classical algorithms. We finally study a possible algorithm improvement by combining it with the quantum Zeno effect.

Exploration of pulse shaping and optimal control The ability to accurately control a quantum system is a fundamental requirement in many areas of modern science such as quantum information processing and the coherent manipulation of molecular systems. It is usually necessary to realize these quantum manipulations in the shortest possible time in order to minimize decoherence, and with a large stability against fluctuations of the control parameters. While optimizing a protocol for speed leads to a natural lower bound in the form of the quantum speed limit rooted in the Heisenberg uncertainty principle, stability against parameter variations typically requires adiabatic following of the system. The ultimate goal in quantum control is to prepare a desired state with 100% fidelity. We experimentally implemented optimal control schemes that achieve nearly perfect fidelity for a two-level quantum system realized with Bose-Einstein condensates in optical lattices. By suitably tailoring the time-dependence of the system's parameters, we transformed an initial quantum state into a desired final state through a short-cut protocol reaching the maximum speed compatible with the laws of quantum mechanics. In the opposite limit we implemented the recently proposed transitionless superadiabatic protocols, in which the system perfectly follows the instantaneous adiabatic ground state. We demonstrated that superadiabatic protocols are extremely robust against parameter variations, making them useful for practical applications. References: 1) Amit Agarwal, Marco Polini, Rosario Fazio, and G. Vignale, Phys. Rev. Lett. 107, 077004 (2011) 2) F. Giazotto, P. Spathis, S. Roddaro, S. Biswas, F. Taddei, M. Governale and L. Sorba, Nature Physics (2011)

doi:10.1038/nphys2053 3) Mark G. Bason, Matthieu Viteau, Nicola Malossi, Paul Hillery, Ennio Arimondo, Donatella Ciampini, Rosario Fazio, Vittorio

Giovannetti, Riccardo Mannella, and Oliver Morsch, Nature Phys. 8, 147-152 (2012) doi: 10.1038/nphys2170 4) Tommaso Caneva, Tommaso Calarco, Rosario Fazio, Giuseppe E. Santoro, and Simone Montangero, Phys. Rev.

A 84, 012312 (2011) 5) Angelo Russomanno, Stefano Pugnetti, Valentina Brosco, and Rosario Fazio, Phys. Rev. B 83, 214508 (2011) 6) Davide Rossini, Vittorio Giovannetti, and Rosario Fazio, Phys. Rev. B 83, 140411 (2011) 7) Nicola Paradiso, Stefan Heun, Stefano Roddaro, Davide Venturelli, Fabio Taddei, Vittorio Giovannetti, Rosario Fazio, Giorgio

Biasiol, Lucia Sorba, and Fabio Beltram, Phys. Rev. B 83, 155305 (2011) 8) D. Venturelli, V. Giovannetti, F. Taddei, R. Fazio, D. Feinberg, G. Usaj, and C. A. Balseiro, Phys. Rev. B 83, 075315 (2011) 9) Pietro Silvi, Fabio Taddei, Rosario Fazio, Vittorio Giovannetti, J. Phys. A: Math. Theor. 44 145303 (2011) 10) Davide Rossini, Vittorio Giovannetti, Rosario Fazio, J. Stat. Mech. (2011) P05021 11) Antonio Negretti, Rosario Fazio, Tommaso Calarco, J. Phys. B: At. Mol. Opt. Phys. 44, 154012 (2011) 12) Biswajit Karmakar, Davide Venturelli, Luca Chirolli, Fabio Taddei, Vittorio Giovannetti, Rosario Fazio, Stefano Roddaro,

Giorgio Biasiol, Lucia Sorba, Vittorio Pellegrini, and Fabio Beltram, " Controlled coupling of spin-resolved quantum Hall edge states", arXiv: 1106:3965

13) J. Nehrkorn, S. Montangero, A. Ekert, A. Smerzi, R. Fazio, T. Calarco, "Staying adiabatic with an unknown energy gap", arXiv:1105:1707

14) Giovanni Vacanti, Stefano Pugnetti, Nicolas Didier, Mauro Paternostro, G. Massimo Palma, Rosario Fazio, Vlatko Vedral, " Photon production from the vacuum close to the super-radiant transition: When Casimir meets Kibble-Zurek", arXiv:1107:0178 (to be published in Phys. Rev. Lett.)

15) G. Vacanti, R. Fazio, M.S. Kim, G.M. Palma, M. Paternostro, V. Vedral, "Geometric phase kickback in a mesoscopic qubit-oscillator system" arXiv:1108:0701 (to be published in Phys. Rev. A)

16) Luca Chirolli, Vittorio Giovannetti, Rosario Fazio, Valerio Scarani, "Time-bin entanglement of quasi-particles in semiconductor devices" arXiv:1101.4767 (to be published in EPL)

17) Nicolas Didier, Stefano Pugnetti, Yaroslav M. Blanter, and Rosario Fazio, Phys. Rev. B 84, 054503 (2011) 18) Nicolas Didier, Stefano Pugnetti, Yaroslav M. Blanter and Rosario Fazio, arXiv:1201.6293.

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III .3.12. Summary of the work performed at UPV/EHU during M13-M24 1.2 Advanced Readout Techniques 1.2.4. Quantum-optics inspired readout methods

M1.9: Design of high-fidelity qubit readout techniques inspired in quantum-optical concepts (18m)

Done and reported at the Y1 review: B. G. U. Englert, G. Mangano, M. Mariantoni, R. Gross, J. Siewert, and E. Solano, “Mesoscopic shelving readout of superconducting qubits in circuit quantum electrodynamics”, Phys. Rev. B 81, 134514 (2010).

1.4 Design and implementation of protocols and algorithms that make maximal use of the available hardware 1.4.2 Efficient qubit gates M1.8: Design of a toolbox of resonant two-qubit gates (18m)

Done and reported at the Y1 review: G. Haack, F. Helmer, M. Mariantoni, F. Marquardt, and E. Solano, “Resonant quantum gates in circuit quantum electrodynamics”, Phys. Rev. B 82, 024514 (2010). 4.5 Quantum communication Communication betwen qubits via cavities. Both milestones M4.7 (12m) and M4.8 (24m), were already passed and reported at the Y1 review. 5.1 Microwave engineering 5.1.5 Microwave photon detectors with qubit clusters (UPV/EHU) Finished during Y1: B. Peropadre, G. Romero, G. Johansson, C. Wilson, E. Solano, and J. J. García-Ripoll, “Perfect Microwave Photodetection in Circuit QED", Phys. Rev. A 84, 063834 (2011). 5.1.6 Propagating quantum microwave fields and qubit clusters (UPV/EHU)

We have introduced an architecture for a photonic crystal in the microwave regime based on superconducting transmission lines interrupted by Josephson junctions. A study of the scattering properties of a single junction in the line showed that the junction behaves as a perfect mirror when the photon frequency matches the Josephson plasma frequency. We generalized our calculations to periodic arrangements of junctions, demonstrating that they can be used for tunable band engineering, forming what we call a quantum circuit crystal. As a relevant application, we discussed the creation of stationary entanglement between two superconducting qubits interacting through a disordered medium.

See D5. This task is now complete: D. Zueco, J. J. Mazo, E. Solano, and J. J. García-Ripoll, “Microwave photonics with Josephson junction arrays”, arXiv:1110:1184. 5.5 Quantum simulation of physical quantum systems 5.5.1 Simulation of useful many-body Hamiltonians Not done. Termination of task and cancellation of Milestone M5.15: requested, due to higher priority for other research lines. 5.5.2 Simulation of quantum relativistic dynamics in circuit QED

Design of protocols for generating and measuring multipartite entangled qubit states inside waveguides: We present a method of implementing ultrafast two-qubit gates valid for the ultrastrong coupling (USC) and deep strong coupling (DSC) regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics (QED) technology. Our proposal includes a suitable qubit architecture and is based on a four-step sequential displacement of an intracavity mode, operating at a time proportional to the inverse of the

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resonator frequency. Through ab initio calculations, we have shown that these quantum gates can be performed at subnanosecond time scales, while keeping the fidelity above 99%. This proposal can be scaled up to several qubits, leading to the generation of circuit-based multipartite entanglement [10]. Design of protocols for the simulation of quantum relativistic dynamics in circuit QED: We proposed a method to get experimental access to the physics of the ultrastrong (USC) and deep strong (DSC) coupling regimes of light-matter interaction through the quantum simulation of their dynamics in standard circuit QED. The method makes use of a two-tone driving scheme, using state-of-the-art circuit-QED technology, and can be easily extended to general quantum optical cavity-QED setups. We provided examples of USC/DSC quantum effects that would be otherwise unaccessible. In particular, we proved that the 1+1 Dirac equation is a particular case of the simulated quantum Rabi model [9].

NEW EMERGING ONGOING RESEARCH PROJECTS

The UPV-EHU team is satisfied with the advances in milestones and tasks. A few delays and postponed work have to do with new research projects that we have started in three cutting-edge frontlines: quantum propagating microwaves, ultrastrong coupling regime, and quantum simulation in circuit QED. We expect these novel fields to become the dominant ones in the context of quantum information and circuit QED technologies in the near future.

Ultrafast quantum gates in circuit QED: We have proposed the design of ultrafast quantum gates in circuit QED by means of the access and suitable manipulation of the ultrastrong coupling regime in the qubit-cavity system [10].

Quantum dynamics of integrable quantum Rabi model: We are considering the use of the analytical solutions of the quantum Rabi model, recently proposed by Daniel Braak in Phys. Rev. Letters, to improve our understanding and physical intuition on the ultrastrong and deep strong coupling regime in circuit QED. This will help us to propose and describe different quantum information protocols at higher operation speed (36m).

CONFERENCE PARTICIPATION AND ORGANIZATION

1) Organizer of Workshop "Quantum simulations", sponsored by SOLID, Benasque, Spain (March 2011).

2) Workshop “Quantum Science and Technology”, sponsored by SOLID, member of the Scientific Committee, Rovereto, Italy (May 2011).

3) Central European Workshop on Quantum Optics (CEWQO), invited talk and member of the Advisory Board, Madrid, Spain (June 2011).

4) Workshop "Social responsability of science", Universidad del País Vasco, San Sebastián, Spain (August 2011). References:

1) R. Gerritsma, B. Lanyon, G. Kirchmair, F. Zähringer, C. Hempel, J. Casanova, J. J. García-Ripoll, E. Solano, R. Blatt, and C. F. Roos, "Quantum simulation of the Klein Paradox", Editorial featuring as "Suggestion" and "Physics Synopsis", Phys. Rev. Lett. 106, 060503 (2011).

2) L. Lamata, J. Casanova, R. Gerritsma, C. F. Roos, J. J. García-Ripoll, and E. Solano, “Relativistic quantum mechanics with trapped ions”, New J. Phys. 13, 095003 (2011).

3) E. Solano, ``Viewpoint: The dialogue between quantum light and matter'', Physics 4, 68 (2011).

4) J. Casanova, C. Sabín, J. León, I. L. Egusquiza, R. Gerritsma, C. Roos, J. J. García-Ripoll, and E. Solano, "Quantum Simulation of the Majorana Equation and Unphysical Operations", Phys. Rev. X 1, 021018 (2011).

5) B. Peropadre, G. Romero, G. Johansson, C. Wilson, E. Solano, and J. J. García-Ripoll, "Approaching perfect Microwave Photodetection in Circuit QED", Phys. Rev. A 84, 063834 (2011).

6) J. Casanova, L. Lamata, I. L. Egusquiza, R. Gerritsma, C. F. Roos, J. J. García-Ripoll, and E. Solano, “Quantum simulation of quantum field theories in trapped ions”, Phys. Rev. Lett. 107, 260501 (2011).

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7) L. Lamata, J. Casanova, I. L. Egusquiza, and E. Solano, “The nonrelativistic limit of the Majorana equation and its quantum simulation in trapped ions”, Phys. Scr. T147, 014017 (2012).

8) Y. M. Wang, D. Ballester, G. Romero, V. Scarani, and E. Solano, "Validity of resonant two-qubit gates in the ultrastrong coupling regime of circuit QED", Phys. Scr. T147, 014031 (2012).

9) D. Ballester, G. Romero, J. J. García-Ripoll, F. Deppe, and E. Solano, “Quantum simulation of the ultrastrong coupling dynamics in circuit QED”, submitted to Physical Review X (2012).

10) G. Romero, D. Ballester, Y. M. Wang, V. Scarani, and E. Solano, “Ultrafast Quantum Gates in Circuit QED”, to be published in Physical Review Letters (2012); arXiv:1110.0223.

11) F. Caruso, S. K. Saikin, E. Solano, S. F. Huelga, A. Aspuru-Guzik, and M. B. Plenio, “Probing Biological Light-Harvesting Phenomena by Optical Cavities”, to be published in Physical Review B (2012).

12) C. E. López, F. Lastra, G. Romero, E. Solano, and J. C. Retamal, “Multipartite entanglement generation assisted by inhomogeneous coupling”, to be published in Physical Review A (2012).

13) T. Bastin, P. Mathonet, and E. Solano, "Operational Entanglement Families of Symmetric Mixed N-Qubit States", submitted to Physical Review Letters (2012).

14) J. Casanova, C. E. López, J. J. García-Ripoll, C. F. Roos, and E. Solano, "Quantum tomography in position and momentum space", submitted to Physical Review A (2012).

15) M. Bina, G. Romero, J. Casanova, J. J. García-Ripoll, A. Lulli, F. Casagrande, and E. Solano, “Solvable model of dissipative dynamics in the deep strong coupling regime”, submitted to Phys. Rev. A (2011).

16) T. Niemczyk, F. Deppe, E. P. Menzel, M. J. Schwarz, H. Huebl, F. Hocke, M. Häberlein, M. Danner, E. Hoffmann, A. Baust, E. Solano, J. J. García-Ripoll, A. Marx, and R. Gross, “Selection rules in a strongly coupled qubit-resonat system”, to be published in Phys. Rev. B (2011).

17) D. Zueco, J. J. Mazo, E. Solano, and J. J. García-Ripoll, “Microwave photonics with Josephson junction arrays”, submitted to Physical Review Letters (2011); arXiv:1110:1184.

18) J. Casanova, A. Mezzacapo, L. Lamata, and E. Solano, “Quantum Simulation of Interacting Fermions Lattice Models in Trapped Ions”, submitted to Physical Review Letters (2011).

19) A. Mezzacapo, J. Casanova, L. Lamata, and E. Solano, “Topological Qubits with Majorana Fermions in Trapped Ions”, submitted to Physical Review Letters (2011).

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III.4. WP1 – Josephson junction (JJ) qubits (Chalmers) A full acount is given in Deliverable D1. Below we present a brief assessment of the status of WP1.

III .4.1. Deviations and corrective actions With respect to the work plan for WP1, the major deviations during the 2nd project year are as follows:

• Multi-qubit (≥3) cQED platforms with qubit coupling resonator and individual qubit readout not yet operational (works for 2 qubits; 4 qubits are being tested, with clear progress).

• As a result, M1.4 and M1.6 are also delayed.

No particular corrective actions needed. Work is in full progress.

III .4.2. Work in WP1 during Y3 • Characterisation and operation of multi-qubit registers with readout of individual qubits coupled

through a common oscillator bus. • Multi-qubit platforms: single-shot QND readout of individual qubits. • Quantitative determination of readout fidelities for 1- and 2-qubit readout for multi-qubit • platforms. • Demonstration and tomographic characterization of universal gate operation on multi-qubit

platforms. • Experimental implementation of algorithms and protocols on multi-qubit platforms.

III.5. WP2 – Semiconductor spin qubits (TUD) A full acount is given in Deliverable D2. Below we present a brief assessment of the status of WP2.

III .5.1. WP2 Deviations and corrective actions With respect to the work plan for WP1, the major deviations during the 2nd project year are as follows: • Delays were caused by the unfortunate alignment of the gate pattern with respect to the crystal

axis (Vandersypen). It is more realistic to aim at a two-qubit protocol in Y3. No particular corrective actions needed. Work is in full progress.

III .5.2. Work in WP2 during Y3 We will continue along the lines planned in the proposal and build on the success achieved in M1-M24. Scaling and the realization of quantum protocols will become the focus during Y3.

III.6. WP3 – Spin qubits in NV centres in diamond (USTUTT) A full acount is given in Deliverable D3. Below we present a brief assessment of the status of WP3.

III .6.1. Deviations and corrective actions Work in WP3 is continuing according to plan. No corrective actions need to be taken at this stage.

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III .6.2. Work in WP3 during Y3 The upcoming project period will be used to demonstrate entanglement of defects over distance by photon interference. Also entanglement storage and eventually entanglement pumping will be further targets. Improving the photon interface by refining photonic and potentially plasmonic structures will be additional targets. Work towards improved coupling will eventually lead to high fidelity entanglement generation in dipolar-coupled arrays. Here entanglement of more than two defects is a definite goal of the upcoming work period.

III.7. WP4 – Hybrid devices and quantum interfaces (CEA) A full acount is given in Deliverable D4. Below we present a brief assessment of the status of WP4.

III .7.1. Deviations and corrective actions Some of the goals seem to be too ambitious to be achieved with in Y3: the quantum interfaces envisioned, such as the spin-qubit interface and the spin-photon interface are not yet within reach of the consortium. Nevertheless, they represent a very valuable goal that the consortium will continue to aim at. No particular corrective actions needed.

III .7.2. Work in WP4 during Y3 The different routes initiated by the consortium will continue for all work packages. A main issue that the consortium will have to address is the potential of hybrid structures for QIP. For Task 4.1, quantum dots coupled to superconducting resonators will be further developed. The possibly too ambitious realization of a quantum interface between a qubit and a spin might not be reached during Y3. For Task 4.2, achieving the strong coupling of a resonator to a spin ensemble is now becoming a routine operation. For a transmon coupled to a NV spin ensemble, improving the memory fidelity and the memory time will be the main goal. In this respect, although the milestone 4.5 has been formally passed, the memory achieved is not useful for quantum information. For phase qubits and TLSs, the future work is not yet very clear. Given the recent progress achieved on the coherence time of transmons, the rationale for hybrids is a bit shifted towards reaching even longer memory times. In this respect, exploiting nuclear spins coupled to NVs, as already demonstrated by USTUTT, is worth being more considered in the long term. For Task 4.3, the efficient quantum emitters obtained with quantum wells in nanowires will be further developed, probably in various directions. Again, obtaining an operational spin-photon interface might not be achieved during Y3. Task 4.4 is expected to advance at a regular pace.

III.8. WP5 – Solid-state quantum technologies (IPHT) A full acount is given in Deliverable D5. Below we present a brief assessment of the status of WP5.

III .8.1. Deviations and corrective actions With respect to the work plan for WP5, the major deviations during the 2nd project year are as follows:

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• M5.1 Development of parametric readout for qubits is delayed. The correspondig Task 5.1.1 is delayed, but in good progress.

• M5.2 Determination of the dephasing and relaxation rates for the solid-state quantum system with a meta-materials engineered dielectric environment. The correspondig Task 5.1.4 is delayed, but in good progress.

• M5.15 Design of protocols for the simulation of useful many-body Hamiltonians in circuit QED. This corresponding task 5.5.1 is now given very low priority due to more urgent lines of research involving ultrastrong coupling cQED for qubit operation.

Corrective action: Request for termination of task: 5.5.1 Simulation of useful many-body Hamiltonians, and cancellation of the corresponding Milestone M5.15.

III .8.2. Work in WP5 during Y3 • Achieveing parametric readout for qubits. • Determination of the dephasing and relaxation rates for the solid-state quantum system with a • meta-materials engineered dielectric environment. • Development of an operational multipartite entanglement characterization and classification for

Circuit QED. • Tsask 5.2.4 “Spin-photon inter-conversion using solid state nanocavities” will be redirected

toward solid immersion lenses (SIL) instead of nanocavitites. • Determination of the dephasing and relaxation rates for the solid-state quantum system with

improved dielectric environment. • Experimental demonstration of lasing with two qubits coupled to a cavity and/or two cavities

coupled to qubit.

III.9. WP6 - Dissemination, training and integration (TUM) A full acount is given in Deliverables D6 and D6.4.

III .9.1. WP6 Deviations and corrective actions With respect to the work plan for WP6, the major deviations during the second project year are as follows:

• The general workshop was moved to Y3, and took place Feb 20-23, 2012 in Grenoble, organised by CNRS/UJF.

III .9.2. Work in WP6 during Y3 To establish a central resource of scientific know how, such as:

• A pedagogical pool of scientific and technical literature and tutorials. • An indexed library of documented simulation software and contact persons. • A continuously updated library of electronic learning material, tutorial lectures, relevant

course materials etc.

To further develop the platform for training of young researchers via collaborative visits of SOLID partners.

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III.10. WP7 – Assessment of systems integration and operation (KIT) The purpose of this workpackage is to provide an in-depth critical self-evaluation of the SOLID progress, measured against objectives, milestones, and state of the art. The goal is to make the analysis sufficiently comprehensive and explicit that it can serve to make the strategic and tactical choices and decisions needed for the Work Programme of the third (and fourth) years of SOLID. A full acount is given in Deliverable D7. Below we present a brief assessment of the status of WP7.

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IV. Deliverables and Milestones tables

Table of Deliverables from start of the project

Del. #

Deliverable name

WP # Leader Na-

ture

Dissemination

Lev’l

Due date

Delivered

Yes/No

Actual/ forecast delivery

date

Comments

D1 Report on Josephson-junction based qubit circuits.

WP1 Chalmers R PU M12

M24 Yes Yes

M12 M24

D2 Report spin-based qubit circuits.

WP2 TUD R PU M12 M24

Yes Yes

M12 M24

D3 Report on spin-based qubits in NV-centers.

WP3 USTUTT R PU M12

M24 Yes Yes

M12 M24

D4 Report on hybrid systems and interfaces.

WP4 CEA R PU M12

M24 Yes Yes

M12 M24

D5 Report on solid-state quantum technologies.

WP5 IPHT R PU M12

M24 Yes Yes

M12 M24

D6.1 SOLID kick-off workshop WP6 TUM O+R PU M3 Yes M2

D6.2 First version of a public and internal SOLID website

WP6 TUM O+R PU M3 Yes M3

D6.3 First technique-orientated summer school

WP6 TUM O+R PU M18 Yes M12 Replaced by Munich workshop 7-8 Oct 2010

D6.4 Direct training activities available to the consortium

WP6 TUM R

PU M18 Yes M24

D6.5 Report from SOLID workshop

WP6

TUM R

PU M24 Yes

M24

Delft 16-17 Jan 2012; Grenoble 20-23 Feb 2012; Reported in D6.4

D6.6 Report from international conference and SOLID workshop

WP6 TUM R

PU M36 -- M44

D7 In-depth critical evaluation of the SOLID progress

WP7 KIT R PU M12

M24 Yes Yes

M12 M24

D8.1 Intermediate report on scientific progress and management


M18 Yes Yes

M8 M18

D8.2 Annual report on scientific progress and management


M24 Yes Yes

M12 M24

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Table of Milestones for the second period

Mil. # Milestone name WP

#

Lead contrac-

tor

Due date

Achieved Yes/ No

Actual/ forecast delivery

date Comments

M1.1

Characterisation and operation of multi-qubit registers (3-6 qubits) with readout of individual qubits coupled through a common oscillator bus.

WP1

CEA TUD

ETHZ USTUTT

KIT IPHT

M24 M36 YES M24

Passed for 2 qubit circuits. 4-qubit registers with common readout are currently being characterized and operated (under testing) (CEA)

M1.2 Multi-qubit platforms: single-shot QND readout of individual qubits.

WP1 CEA

M18

YES M24-M30

Passed for 2 qubit circuits. 4-qubit registers with common readout are currently being characterized and operated (under testing) (CEA)

M1.3

Quantitative determination of readout fidelities for 1- and 2-qubit readout for multi-qubit platforms.

WP1 CEA M24 M36

NO In pro-gress

M36

Passed for 2 qubit circuits. 4-qubit registers with common readout are currently being operated (tested) (CEA)

M1.4 Several platforms will achieve readout fidelity of >> 90% for a single qubit.

WP1 CEA TUD

ETHZ

M24 M36 YES M24

Passed by CEA, TUD and ETHZ.

M1.5 Preparation, readout and tomography of states with 2-4 entangled qubits.

WP1 CEA ETHZ

M18 YES M18

Passed by ETHZ and CEA

M1.6 Demonstration and tomographic characterization of universal gate operation on multi-qubit platforms.

WP1 CEA

ETHZ M24 M36 YES M24

Passed by ETHZ (and by CEA for 2-qubit registers)

M1.7 Experimental implementation of algorithms and protocols on multi-qubit platforms (Bell mesurements; teleportation; coding; Grover; Deutsch-Jozsa; Iterative Phase Estimation.

WP1 CEA ETHZ

USTUTT

M24 M36 YES M18-M24

Bell; Grover; coding step of teleportation; Toffoli gate

M1.8 Design of a toolbox of resonant two-qubit gates

WP1 UPV/EHU M18

YES M12

M1.10 Design of high-fidelity qubit readout techniques inspired in quantum-optical concepts

WP1 UPV/EHU M18 YES M12

M2.1 Demonstration of integrated spin qubit functionality in a

WP2 TUD M12 YES M18 Read-out, exchange and single-spin inversion

SOLID FP7 248629 2012-04-01



two-qubit device realized. Single-spin pi/2 rotations will follow.

M2.2 Decision on whether to use geometric gates in experiments.

WP2 TUD M12 YES M12

Do NOT use geometric gates at this stage.

M2.3 Demonstration of 1 ms single-electron spin dephasing time.

WP2 TUD M18 NO M36

Started measurements on Si/SiGe quantum dots

M2.4 Demonstration of a simple quantum protocol on two spin qubits in quantum dots.

WP2 TUD M18 NO M36

M2.5 Demonstration of universal spin qubit functionality in a scalable, three-qubit system.

WP2 TUD M36 -- M36

We aim at partial control of a three-qubit device

M2.6 Demonstration of electron spin state teleportation between quantum dots

WP2 TUD M36 -- M36

This is a possible choice of the simple protocol (M2.4)

M3.1 Create single color centers in

diamond with depleted 13C concentration.

WP3 USTUTT M18 YES

M18

M3.2 Demonstrate coherent coupling between two defects separated by more than 20 nm.

WP3 USTUTT M24 M36 YES

M24

Paper in submission process

M3.3 Evaluate coherence time and possibility to reach T1 limit for single spins in isotopically engineered diamond.

WP3 USTUTT M24

YES

M24 Improved temperature stability

M3.4 Robust deterministic entanglement for small quantum register consisting of 4-8 spins in diamond.

WP3 USTUTT M24 M36

NO In pro-gress

M36

4 spin entanglement (2 electron- 2 nuclei) has been achieved

M4.1 Realisation of hybrid systems for quantum information processing on different platforms.

WP4 CEA M24 M36 YES M24

M36

Transmon couled to NV spins through a resonator (CEA). Phase qubit coupled to TLS (KIT)

M4.2 Demonstration of the coupling between spin qubits and photonic states (microwave or optical).

WP4 CEA

Chalmers

KIT

M24 M36 YES

M24 M36

M4.3 Demonstration of the coupling between different types of qubits in hybrid structures

WP4 CEA

KIT M24 M36 YES M24

M36

Transmon coupled to NVC (CEA) Phase qubit coupled to TLSs (KIT)

M4.4 Demonstration of reversible information transfer in a hybrid structure.

WP4 CEA

KIT

M24 M36 YES M24

M36

Phase qubit to TLS (KIT), and transmon to NV spin ensemble (CEA)

M4.5 Demonstration of a quantum memory in a hybrid structure, evaluation of the storage performance.

WP4 CEA M36

YES M24

NV spin ensemble for transmon (CEA); limited memory performance

M4.6 Achieve coherent coupling between single NV defect and optical microresonator.

WP4 USTUTT

TUD

M36 -- M36

In progress

SOLID FP7 248629 2012-04-01



M4.7 Design of multiqubit-multicavity coupling to achieve quantum information tasks.

WP4 UPV/EHU M12 YES

M12 (theory) Termin.

(exp)

UPV/EHU (Theory) Not possible for the experimental SOLID projects

M4.8 Design of sequential protocols for generating multipartite entangled qubits.

WP4 UPV/EHU M24 YES

M12

M5.1

Development of parametric readout for qubits.

WP5 Chalmers M18 NO In pro-gress

M36 In progress

M5.2 Determination of the dephasing and relaxation rates for the solid-state quantum system with a meta-materials engineered dielectric environment.

WP5 IPHT M24 NO

In pro-gress

M30-M36

First measurements performed

M5.3 Design of metamaterials, in the context of Circuit QED, for implementing realistic microwave photon detectors and photon counters with propagating quantum microwave fields acting on qubit/clusters inside waveguides.

WP5 IPHT Chalmers

M18

YES

M24-M36

Work continues during Y3

M5.4 Development of a theory for propagating quantum microwaves interacting with one qubit or more qubits inside waveguides in Circuit QED.

WP5 UPV/ EHU

M18

YES

M18

M5.5 Development of an operational multipartite entanglement characteri-zation and classification for Circuit QED.

WP5 UPV/ EHU

M36

--

M36

M5.6 Spin-photon inter-conversion using solid state nanocavities

WP5 TUD M36 --

M36 Nanocavities will be replaced by SIL (solid immersion lenses)

M5.7

Electrically tunable single dot nanocavities

WP5 TUM M18 YES

M18

M5.8

Coherent preparation of hole spin state

WP5 ETHZ M18 --

M18 Cancelled (Y1 review)

M5.9

Coupling of NV centers to solid-state photonic structures

WP5 TUD M18 YES

M18 App. Phys. Lett. 98, 193103 (2011)

M5.10

Determination of the dephasing and relaxation rates for the solid-state quantum system with improved dielectric environment.

WP5 IPHT M18

M18

M5.11

Experimental demonstration of lasing with a single flux qubit

WP5 IPHT M18 YES

M24

M5.12

Experimental demon-stration of lasing with two qubits coupled to a cavity

WP5 IPHT M36 --

M36

SOLID FP7 248629 2012-04-01



and/or two cavities coupled to qubit.

M5.13

Design of protocols for generating and measuring multipartite entangled qubit states inside waveguides.

WP5 UPV/ EHU

M24

YES

M24

M5.14

Design of protocols for generating and reconstructing the state or phase-space representation (e.g., Wigner function) of propagating quantum microwaves

WP5 UPV/ EHU

M18

YES

M18

M5.15 Design of protocols for the simulation of useful many-body Hamiltonians in circuit QED.

WP5 UPV/ EHU

M18

NO

Termi-nate

Corrective action requested

M5.16 Design of protocols for the simulation of quantum relati-vistic dynamics in circuit QED.

WP5 UPV/ EHU

M18 YES

M18

M6.1 SOLID kick-off workshop WP6 TUM M2 YES M2

M6.2 First version of a public and inernal web page

WP6 TUM M3 YES M3

M6.3 Technique-orientated summer school (ESONN, Aug. 2010)

WP6 TUM M12 YES M14

Replaced by Munich Workshop 7-8 Oct 2010

M6.4 SOLID workshop with participation of AQUTE and Q-Essense (Sept. 2011)

WP6 TUM M24 YES M25

Grenoble Feb 20-23, 2012

M6.5 International conference and SOLID workshop (Sept. 2012)

WP6 TUM M36 -

M36-M44

To be replaced by SOLID multi-topical workshop autumn 2012. Int conf during 2013.

M7 Analysis of SOLID progress and formulation of specific recommendations every 6 months.

WP7 KIT/ Chalmers M18

M24 YES M18 M24

See D7

SOLID FP7 248629 2012-04-01



V. Project Management (WP8 – Chalmers – Göran Wendin)

V.1. WP8 objectives WP8 is dedicated to the overall coordination. It includes the strategic management that relates the consortium research orientations beyond the end of the project with the short-term actions of the project. It also encompasses the operational management that consists in establishing the project management plan, managing the interfaces and interactions between the WPs, and ensuring the successful cooperation of the different WPs. WP8 is also dedicated to the technical coordination of the project, more precisely of the WPs. It includes the management of the technical tasks, the periodic assessment and management of risks, the monitoring of the deliverables production. Each WP leader will be responsible of his WP, following the progress, reporting to the Steering committee and ensuring that all milestones and deliverables are fulfilled. The WP8 lead partner is Chalmers, acting as the coordinator of the project. All Workpackage leaders also contribute to WP8 in implementing the management of their respective WP.

V.2. Consortium Management tasks and achievements During the second period of the project, the main management task has consisted in managing SOLID finances and reporting, communicating with the Partners, keeping track of the SOLID progress, submitting the SOLID/EntangleMe INCO extension, and co-organising several workshops. See WP6 and deliverable D6.4. The advance payment of € 2 416 667 from the European Commission was received by the Project Coordinator in December 2009 and was distributed to the project partners in one instalment via a payment request to Chalmers administration on 19 January 2010. The second payment of € 1 267 723 was issued on 12 August 2011. The detailed figures are shown in Table V.1 below:

Table V.1 Payments form the Coordinator to the Partners.

The SOLID financial situation is shown in Table V.2 below:

SOLID FP7 248629 2012-04-01



Budget Y1+Y2 Remains Y3 Budget/3

Table V.2 Actual spending by the SOLID partners during the first two years (Y1+Y2; the Y2 figures are taken from the current Form C). The last column gives the average yearly spending according to the budget. Regarding the overall spending, SOLID is on target. Concerning individual Partners, The picture is mixed: CEA, TUD and CNRS/UJF have already spent a considerable part of the budget for Y3, while UNIBASEL stand out with severe underspending due to late hiring. Some of the underpending of TUM is due to the fact that TUM is administrating the SOLID WP6 fund for dissemination and integration, and we expect the expenses to grow considerably during Y3. In this context, it should noted that Chalmers will transfer € 50 000 to TUD (for L. Di Carlo, Y1 review decision) via the 3rd payment. This puts Chalmers on target, and TUD with moderate overspending. Finally, since SOLID is in the process of being extended to 44 months due to an INCO extension, underspending at this time is no problem for SOLID as a whole.

V.3. WP8 Deliverables and milestones Deliverables

• D8.1: Intermediate report on scientific progress and management. (M18)

• D8.2: Annual report on scientific progress and management. (M24)

Milestones • No milestones.

V.4. List of Meetings during the period

Date Location Organizer Participant Items addressed/Output

April 14-16, 2011 Warsaw QESSENCE SOLID Y1 review and Open Day

Sept 5-9, 2011 Zürich ETH-Zürich SOLID QIPC’11 clutser conference

Jan 16-17, 2012 Delft TUD SOLID SOLID topical workshop on superconducting circuits

Feb 20-23, 2012 Grenoble CNRS Open SOLID general workshop

SOLID FP7 248629 2012-04-01



V.5. Project planning and status The Coordinators assessment is that SOLID is on an excellent track. M18 was an important checkpoint, and the present results at M24 look very promising: the most important milestones have been passed, or will soon be passed There are no visible barriers: SOLID stays in the frontline, and is often world leading. However, in a somewhat longer perspective there is a question how to meet the enormous competition from the present highly focused programs for Josephson-based superconducting quantum processor circuits developed by several collaborations in the USA.

V.6. Deviations and corrective actions Detailed accounts of deviations and corrective actions are presented in deliverables D1-D7, as well as in Sect. III.4.10 of this report. Deviations during Y2: There are no deviations regarding general SOLID objectives. The only deviations concern minor delays regarding a few milestones, and a request for termination of one task (5.1.1; milstone M5.15; UPV/EHU) due to higher priority put on other tasks during Y3. Corrective actions for Y3: The only RTD-related corrective action concerns termination of task 5.1.1 and cancellation of milestone M5.15. A different “corrective” action consists in going through the amendment procedure to add two new US partners to SOLID, namely UCSB, Santa Barbara, CA and JILA, Boulder, CO. his is the result of a successful FET Open proposal for an INCO extension, SOLID/EntangleMe, to be incorporated as WP9 (TUD, Leo DiCarlo WP-leader) in SOLID, adding € 412 000 to the budget and propnging SOLID by eight months, until 44 months, i.e. 30 September 2013. No change to the legal status of any of the beneficiaries has occurred during Y2.

SOLID FP7 248629 2012-04-01



V.7. Explanation of the use of the resources (Y2: 1 Feb 2011-31 jan 2012)

V.7.1. Direct costs items for beneficiary 1 (Chalmers)

Work Package

Item description Amount €

Explanations

WP1, WP4, WP5, WP7

Personnel costs 138773

0,8 pm permanent staff 22 pm non-permanent staff Permanent researchers: V. Shumeiko C. Wilson Non-Permanent: Matthias Staudt Waltraut Wustmann (from April 2011)

WP8 Management personnel 59454 8,7 pm project coordination: G. Wendin All WPs Travel costs 28892 Meetings, conferences: V.4 and others Registration fees 2275 WP1, WP4, WP5

Equipment 5237

WP1, WP4, WP5

Clean room fee 17864

16% on the experimental part of the grant. Covers most of the fabrication costs, including related consumables.

WP1, WP4, WP5

Consumables 16211 Liquid helium, 13784 €

All WPs Remaining direct costs 3391 Audit certificate, 3261 €, representation 130 €

TOTAL DIRECT COSTS 272097

V.7.2. Direct costs items for beneficiary 2 (CEA)

Work Package


Explanations

WP1, WP4, WP5

Personnel costs 176 231 7,59 pm permanent staff 41,5 pm non-permanent staff Permanent researchers: D. ESTEVE 2,11 pm D. VION : 2,10 pm P. BERTET : 3,38 pm Non-Permanent: P. BARTET 2 pm C. GREZES 4,5 pm Y. KUBO 12 pm R. LAURO 12 pm H PHAM DINH 6 pm V. SCHMITT 5 pm

Travel 5 688,70 Consumables 31 625,36 Electronics, microwave equipment,… Fabrication costs ………. Paid through clean room consumables …………. ………. ………………. Other direct costs 10 319,44 functioning TOTAL DIRECT COSTS 223 864,50

SOLID FP7 248629 2012-04-01



V.7.3. Direct costs items for beneficiary 3 (TUD)

Work Package


Explanations

WP1, WP4, WP5

Personnel costs 96,647.72 0 pm permanent staff 22.5 pm non-permanent staff Non-Permanent: Katja Nowack(Postdoc Feb/2011->Mar2011) Edward Laird (Postdoc Feb/2011->Oct2011) Tim Taminiau (Postdoc Mar/2011->Jan2012)

Travel 8,090.17 Bilbao kick-off meeting; Munich workshop Consumables 72,752.28 Helium, Electronics parts Fabrication costs 0 Other direct costs 0 TOTAL DIRECT COSTS 177.490.00

V.7.4. Direct costs items for beneficiary 4 (ETHZ)

Work Package

Item description Amount

Explanations

WP1 WP2 WP4 WP4

Personnel cost

55’172.68

37’955.05

54’586.03

12’912.60

Non-Permanent:

PhD student Lars Steffen (12 mt, 75%)

PhD student Emre Ilgünsatiroglu (9 mt, 75%)

PhD student Tobias Frey (12 mt, 75%)

Post Doc Parisa Fallahi (1.5 mt)

All WP Travel costs 3’347.79 Attendance of SOLID meetings and workshops, QIPC Conference.

Equipment costs

-

No Equipment costs

All WP Materials + Consumables 16’495.48

Materials and consumables to run the specified experiments focused on electrical transport and optical measurements.

TOTAL DIRECT COSTS 180 469.64

SOLID FP7 248629 2012-04-01



V.7.5. Direct costs items for beneficiary 5 (KIT)

Work Package


Explanations

WP1 WP1 WP1 WP1+WP5 WP1+WP5 WP1+WP5 WP 1 WP 1 WP 1+WP5 WP1,2,4,5 WP1,2,4,5

Personnel costs

113 798,49

7.5 pm permanent staff 42 pm non-permanent staff Dr. Stefano Poletto 01.02.11-31.05.11 Philipp Jung 15.10.11-31.01.12 Susanne Butz (Hiwi) 15.06.11-31.12.11 Steffi Baatz 01.02.11-31.01.12 Prof. Alexey Ustinov (148 hrs) Dr. Jürgen Lisenfeld (545 hrs) Lingzhen Guo (Hiwi) 01.03.11-31.01.12 Andreas Heimes 01.07.11-31.12.11 Stephan André 01.01.12-31.01.12 Prof. Gerd Schön (194 hrs) Prof. Dr. A. Shnirman (188 hrs)

Travel/Guests (Exp.) “ (Theory)

3.070,84 1.396,64

Registration Fees (Exp. + Theory)

405,39

WP1+WP5 WP1+WP5 WP1+WP5 WP5

Consumables 5.875,83 1.428,48 electronic parts 3.709,22 other materials 1.350,00 repair bonder 738,13 publications

Fabrication costs 0 Other direct costs 0 TOTAL DIRECT COSTS 124.547,19

V.7.6. Direct costs items for beneficiary 6 (IPHT)

Work Package


Explanations

WP1 RTD Personnel 21,102 4.37 pm: P. MACHA (non-permanent) WP5 RTD Personnel 45,648 10.59 pm; S. ANDERS, D. BORN

(permanent) WP1, WP5 RTD Consumables 836 electronics WP1, WP5 RTD Travel 800 travel to SOLID Meeting Warsaw

(IL'LICHEV), conference EUCAS the hague, Netherlands cooperation with SOLID partner KIT (MACHA)

TOTAL DIRECT COSTS 68,386

SOLID FP7 248629 2012-04-01



V.7.7. Direct costs items for beneficiary 7 (CNRS)

Work Package


Explanations

WP1 Personnel costs 111 420.64 6.5 p/m permanent staff (Olivier Buisson) 17.5 p/m non-permanent staff (Florent Lecocq, Alexey Feofanov, Etienne Dumur, Gianluca Rastelli)

WP5 Personnel costs 2 730.96 0.59 p/m permanent staff 0.5 p/m non-permanent staff

Travels 3 947.27 MOROND conference (F. Lecocq)

March meeting in Dallas (F. Lecocq)

SOLID meeting in Warsaw (O. Buisson)

Les Houches School (O. Buisson) Frontiers of Quantum and Mesoscopic Thermodynamics Conference in Prague (F. Hekking)

Consumables 771.96 Electronics+ wafers Fabrication costs 0 Other direct costs 0 TOTAL DIRECT COSTS 118 870.83

Direct costs items for beneficiary 7 (UJF, 3rd party SC 10, linked to CNRS)

Work Package


Explanations

WP1 Personnel costs 27 395.61 3.1 p/m permanent staff (Wiebke Guichard, Frank Hekking)

Travels 0 Consumables 0 Fabrication costs 0 Other direct costs 0 TOTAL DIRECT COSTS 27 395.61

SOLID FP7 248629 2012-04-01



V.7.8. Direct costs items for beneficiary 8 (UNIBAS)

Work Package


Explanations

WP2,WP4 Personnel costs 9737.87 2 pm non permanent staff Non-Permanent: Dr. Diego Rainis. (postdoc 12/2010 – 01/2011)

Travel 1187.68 Solid Fall Workshop 7./8. 10.2010 WP2, WP4 Equipment 132.52 Apple iMac,

deprecitation: 12/2010-01/2011 Other direct costs 14.91 Printing of a poster TOTAL DIRECT COSTS 11 072.98

V.7.9. Direct costs items for beneficiary 9 (TUM)

Work Package


Explanations

WP1, WP4, WP5, WP6

RTD-Personnel costs 40.547,75 € 12 pm PhD Student Daniel Rudolph

WP6 WP6 WP6

RTD-Travel 677,09 €

534,49 €

1064,08 €

J. J. Finley – 1st year review, Warsaw, April 2011 D. Rudolph, - Semicon-Nano 2011, Int. Workshop, Sep. 2011, to present results D. Rudolph, MRS Fall Meeting, Boston, Nov 2011, to present results

WP1, WP4, WP5

RTD-Consumables 37.396,76 € Semiconductor substrates, Metal consumables (piece of Titanium), Pigtailed laser diode, Semiconductor handling / inspection tools, (Pippette, Tweezer, Microscope coverslips..), Small Optical Components (Lenses/ Mirrors / Beamsplitter / Filter / Fiber coupler) , Opto-mechanical components (Rotation mount, tilt stages)

WP6 WP6 WP6 WP6

RTD Other direct costs

907,15 €

754,81 €

4.994,00 €

3.000 €

SOLID Training visit (Alessandro Bruno) SOLID Training visit (Borja Peopadre) SOLID contribution to organization of Benasque Workshop on Quantum Simulations, Bilbao, Feb 2011 (http://benasque.org/2011qs/ ) SOLID contribution to organization of quantum sciences and technologies workshop, Rovereto, Italy, May 2011 (http://events.unitn.it/en/qst)

TOTAL DIRECT COSTS 89.422,13€

SOLID FP7 248629 2012-04-01



V.7.10. Direct costs items for beneficiary 10 (USTUTT)

Work Package


Explanations

WP3 Personnel costs- RTD

33.935,66 5 pm non-permanent staff ; Non-Permanent: Dr. Boris Naydenov (postdoc February-June 2011) 5 pm (0,5 contract) non-permanent staff; PhD student D. Schmid-Lorch (Sept.2011 - Jan.2012)

WP3 Travel- RTD 5.989,69 Meeting Bilbao- R. Stöhr for B. Naydenov Meeting Bochum - B.Naydenov Meeting Brussels - F. Jelezko Conference Warsaw - J. Wrachtrup Conference Dallas - J. Wrachtrup (Invited talk, APS March Meeting 2011; presenting SOLID results)

WP3 Consumables - RTD 44.686,25 Small optical parts, small electronic devices, chemicals

WP3 Other direct costs-RTD

603,66 Depreciation of equipment

TOTAL DIRECT COSTS 85.215,26

V.7.11. Direct costs items for beneficiary 11 (SNS)

Work Package


Explanations

WP1, WP5 Personnel cost 50.789,54

pm permanent staff: -Prof. R. Fazio 2 pm pm temporary staff: -Postdoc dr. Davide Rossini 12 pm (hired from 18.10.2010 to 31.01.2013)

WP 1, 5 Travel Cost 5.348,49

Conferences and Workshop: -"Quantum Simulations", 2011, February 28th - March, 5 th, Benasque, (Spain) -"Quantum Science and Technologies", 2011, 9th -12nd May, Rovereto, (Italy) and others Project meeting/workshop: -“Cluster Review" (Review meeting SOLID), 2011, 14th April, Warsaw (Poland) Visits: Davide Rossini visited Universidad del Pais Vasco (scientific collaboration on the project with prof. Enrique Solano’s group) 2011, 6th-8th November, Bilbao (Spain) Seminar: Rossini did a seminar related to the work carried out in the SOLID Project "Dynamics of coupled coupled-cavity networks in the strong coupling regime", 2011, 12nd July, Catania, (Italy)

TOTAL DIRECT COSTS 56.138,03

SOLID FP7 248629 2012-04-01



V.7.12. Direct costs items for beneficiary 12 (UPV/EHU)

Work Package


Explanations

WP1, WP4, WP5

Pesonnel costs 47.736,00 13,71 PM of 2 researchers hired by the project: Daniel Ballester and Antonio Mezzacapo

Travel 12.263,00 Meetings, conferences, research visits Other direct costs TOTAL DIRECT COSTS 59.999,00

VI. Financial Statements In accordance to the FP7 reporting procedure, the financial statements for each beneficiary has been submitted through the online tool "NEF".

VII. Certificates In accordance with Article II.4.45 of the Grant Agreement, only beneficiaries Chalmers and TUD need to provide any certificate on the financial statements for the first period of the project. The accumulated payment refers to real costs, and does not involve the advance payment.

Beneficiary

Organisation short name

Certificate provided Yes/No

Comments, in particular if a certificate is not provided

1 Chalmers (Coordinator) YES Accumulated payment received > 375 k€

2 CEA No Accumulated payment received < 375 k€ 3 TUD No Accumulated payment received >375 k€ 4 ETHZ No Accumulated payment received < 375 k€ 5 KIT-U No Accumulated payment received < 375 k€ 6 IPHT No Accumulated payment received < 375 k€ 7 CNRS No Accumulated payment received < 375 k€ 8 UNIBAS No Accumulated payment received < 375 k€ 9 TUM No Accumulated payment received < 375 k€

10 USTUTT No Accumulated payment received < 375 k€ 11 SNS No Accumulated payment received < 375 k€ 12 UPV/EHU No Accumulated payment received < 375 k€

VIII. References Annex1

Deliverables http://qurope.eu/projects/solid

SOLID FP7 248629 2012-04-01



IX. Annex: Outreach and Publications During the first year of activity the SOLID consortium has released a number of documents for public dissemination. Those documents mainly concern the presentation of the project and are part of the necessary public deliverables. Those documents are being made available through the internet website. The table below gives an overview of the public documents produced during the first year.

Table IX.1 - Public SOLID documents produced Feb 2011-Jan 2012

Documentation type (article, internal report, poster …)

Details (Author, Title, reference, general description, date)

Status: PU=Public CO=Confidential

Table IX.2 – Outreach Feb 2011-Jan 2012 (see also the SOLID web site (http://qurope.eu/projects/solid)

Documentation type (article, internal report, poster …)

Details (Author, Title, reference, general description, date)

Year

Public lecture (TUD)

L.P. Kouwenhoven TEDxDelft, 18 minute presentation on That’s a one centimeter step for man, one giant leap for mankind. Presentation available on YouTube

2011

Outreach Talk (ETHZ)

A. Wallraff Quanten, Bits und Computer - Neue Perspektiven in der Informationstechnologie, ETH Foundation Thanksgiving 2011, Roessler prize talk, ETH Zurich, Switzerland, June 23, 2011

2011

Outreach Talk (ETHZ)

A. Wallraff Quantum science and Technology with Electronic Circuits at Ultra Low Temperatures, Special Event at LT 26 hosted by Oxford Instruments, Beijing, China, August 11, 2011

2011

Beside documents for the general public, publications in scientific conferences and journals are important communication channels for disseminating the research outcomes of the project. The members of the consortium have strong commitment in publishing their work in relation to the SOLID project’s research topics in high quality conferences and major journals. During the 2nd year of the project, the partners have authored or co-authored a number of journal and conference articles on subjects that directly result or benefit from the research work performed within SOLID. The table below lists the major Article or Conference papers published during the first period. The table also lists articles in preparation or submitted as of end January 2012.

SOLID FP7 248629 2012-04-01



Table IX.3 - Scientific Communications and Papers by SOLID partners, Feb 2011-Jan 2012

Type Title Authors Year Details

Article

(Chalmers)

Demonstration of a single-photon router in the microwave regime

Io-Chun Hoi, C. M. Wilson, G. Johansson, T. Palomaki, B. Peropadre, and P. Delsing,

2011 Phys. Rev. Lett. 107, 073601 (2011)

DOI: 10.1103/PhysRevLett.107.073601

Article

(Chalmers)

Rare earth spin ensemble magnetically coupled to a superconducting resonator

P. Bushev, A. K. Feofanov, H. Rotzinger, I. Protopopov, J. H. Cole, C. M. Wilson, G. Fischer, A. Lukashenko, A. V. Ustinov,

2011 Phys. Rev. B 84, 060501(R) (2011) DOI: 10.1103/PhysRevB.84.060501

Article

(Chalmers)

Activation mechanisms for charge noise

M. V. Gustafsson, A. Pourkabirian, John Clarke, and Per Delsing

2012 arXiv 1202.5350

Article

(Chalmers)

Generation of nonclassical microwave states using an artificial atom in 1D open space

Io-Chun Hoi, Tauno Palomaki, Göran Johansson, Joel Lindkvist, Per Delsing, and C M Wilson

2012 arXiv 1201.2269

Article

(Chalmers)

Coupling of an erbium spin ensemble to a superconducting resonator

Matthias U Staudt, Io-Chun Hoi, Philip Krantz, Martin Sandberg, Michael Simoen, Pavel Bushev, Nicolas Sangouard, Mikael Afzelius, V Shumeiko, Göran Johansson, Per Delsing and C. M. Wilson

2012 Accepted for publication in Journal of Physics B, (2012)

Article

(CEA)

Circuit QED with a Nonlinear Resonator: ac-Stark Shift and Dephasing

F. R. Ong, M. Boissonneault, F. Mallet, A. Palacios-Laloy, A. Dewes, A. C. Doherty, A. Blais, P. Bertet, D. Vion, and D. Esteve

2011 Phys. Rev. Lett. 106, 167002 (2011) DOI: 10.1103/PhysRevLett.106.167002

Article

(CEA)

Backaction of a driven nonlinear resonator on a superconducting qubit

M. Boissonneault, A. C. Doherty, F. R. Ong, P. Bertet, D. Vion, D. Esteve, A. Blais

2011 Phys. Rev. A, in press arXiv:1111.0203

Article

(CEA)

Characterization of a two-transmon processor with individual single-shot qubit readout

A. Dewes, F. R. Ong, V. Schmitt, R. Lauro, N. Boulant, P. Bertet, D. Vion, and D. Esteve

2011

Phys. Rev. Lett., in press arXiv:1109.6735

Article

(CEA)

Demonstrating quantum speed-up in a superconducting two-qubit processor

A. Dewes, R. Lauro, F.R. Ong, V. Schmitt, P. Milman, P. Bertet, D. Vion, D. Esteve

2011 Submitted to Phys. Rev. B arXiv:1110.5170

Article

(CEA)

Hybrid Quantum Circuit with a Superconducting Qubit Coupled to a Spin Ensemble

Y. Kubo, C. Grezes, A. Dewes, T. Umeda, J. Isoya, H. Sumiya, N. Morishita H., Abe, S. Onoda, T. Ohshima, V. Jacques, A. Dréau, J.-F. Roch, I. Diniz, A. Auffeves, D. Vion, D. Esteve, and P. Bertet


Article

(CEA)

Storage and retrieval of a microwave field in a spin ensemble

Y. Kubo, I. Diniz, A. Dewes, V. Jacques, A. Dréau, J.-F. Roch, A. Auffeves, D. Vion, D. Esteve, and P. Bertet

Jan 2012

Phys. Rev. A 85, 012333 (2012)DOI:

DOI: 10.1103/PhysRevA.85.012333

Article

(CEA)

Strongly coupling a cavity to inhomo-geneous ensembles of emitters: Potential for long-lived solid-state quantum memories

I. Diniz, S. Portolan, R. Ferreira, J. M. Gérard, P. Bertet, and A. Auffèves,

2011 Phys. Rev. A 84, 063810 (2011) DOI: 10.1103/PhysRevA.84.063810

SOLID FP7 248629 2012-04-01



Article

(TUD)

Single-spin magnetometry with multi-pulse dynamical decoupling sequences

G. de Lange, D. Ristè, V. V. Dobrovitski, R. Hanson 2011 Physical Review Letters106, 080802

(2011)


Article

(TUD)

Spin dynamics in the optical cycle of single nitrogen-vacancy centres in diamond

L. Robledo, H. Bernien, T. van der Sar, R. Hanson 2011 New Journal of Physics13, 025013

(2011).

DOI:: 10.1088/1367-2630/13/2/025013

Article

(TUD)

High-fidelity projective readout of a solid-state spin quantum register

Lucio Robledo, Lilian Childress, Hannes Bernien, Bas Hensen, Paul F. A. Alkemade, Ronald Hanson

2011 Nature 477, 547-578 (2011) DOI:: 10.1038/nature10401

Article

(TUD)

Controlling the quantum dynamics of a mesoscopic spin bath in diamond

G. de Lange, T. van der Sar, M.S. Blok, Z. H. Wang, V.V. Dobrovitski, and R. Hanson,

2011 submitted, see http://arxiv.org/ftp/arxiv/papers/1104/1104.4648.pdf

Article

(TUD)

Single-Shot Correlations and Two-Qubit Gate of Solid-State Spins

K. C. Nowack, M. Shafie, M. Laforest, G. E. D. K. Prawiroatmodjo, L. R. Schreiber, C. Reichl, W. Wegscheider, L. M. K. Vandersypen,

2011 Science 333, 1269 (2011) DOI: 10.1126/science.1209524

Article

(TUD)

Coupling artificial molecular spin states by photon-assisted tunnelling

L.R. Schreiber, F.R. Braakman, T. Meunier, V. Calado, J. Danon, J.M. Taylor, W. Wegscheider & L.M.K. Vandersypen

2011 Nature Communications 2, 556 (2011) DOI:10.1038/ncomms1561

Article

(TUD)

Generating Entanglement and Squeezed States of Nuclear Spins in Quantum Dots

M. S. Rudner, L. M. K. Vandersypen, V. Vuletić, and L. S. Levitov

2011 Physical Review Letters 107, 206806

(2011)


Article

(TUD)

C-Phase gate for single-spin qubits in quantum dots

T. Meunier, V.E. Calado, L.M.K. Vandersypen 2011 Physical Review B 83, 121403 (2011)

DOI: 10.1103/PhysRevB.83.121403

Article

(TUD)

Selective darkening of degenerate transitions for implementing quantum controlled-NOT gates

P. C. de Groot, S. Ashhab, A. Lupascu, L. DiCarlo F. Nori, C.J.P.M Harmans, and J. E. Mooij

2012 Submitted. Available at http://lanl.arxiv.org/abs/1201.3360.

Article

(ETHZ)

Multimode mediated qubit-qubit coupling and dark-state symmetries in circuit quantum electrodynamics

S. Filipp, M. Göppl, J. M. Fink, M. Baur, R. Bianchetti, L. Steffen, and A. Wallraff


Article

(ETHZ)

Characterization of a microwave frequency resonator via a nearby quantum dot

T. Frey, P. J. Leek, M. Beck, K. Ensslin, A. Wallraff, and T. Ihn 2011 Appl. Phys. Lett. 98, 262105 (2011)

http://dx.doi.org/10.1063/1.3604784

Article

(ETHZ)

Preparation of subradiant states using local qubit control in circuit QED

S. Filipp, A. F. van Loo, M. Baur, L. Steffen, and A. Wallraff


Article

(ETHZ)

Implementation of a Toffoli gate with superconducting circuits

A. Fedorov, L. Steffen, M. Baur, M. P. da Silva, and A. Wallraff

2012 Nature 481, 170–172 (2012)

doi:10.1038/nature10713

Article

(ETHZ)

Benchmarking a Quantum Teleportation Protocol in Superconducting Circuits Using Tomography and an Entanglement Witness

M. Baur, A. Fedorov, L. Steffen, S. Filipp, M. P. da Silva, and A. Wallraff


SOLID FP7 248629 2012-04-01



Article

(ETHZ)

Dipole coupling of a double quantum dot to a microwave resonator

T. Frey, P. J. Leek, M. Beck, A. Blais, T. Ihn, K. Ensslin, and A. Wallraff


Article

(KIT-Theory)

Phase-dependent quasiparticle tunneling in Josephson junctions: Measuring the cos φ term with a superconducting charge qubit

J. Leppäkangas, M. Marthaler, and G. Schön 2011 Phys. Rev. B 84, 060505(R) (2011); DOI:

10.1103/PhysRevB.84.060505

Article

(KIT-Theory)

Fragility of multi-junction flux qubits against quasiparticle tunneling

J. Leppäkangas and M. Marthaler 2011 arXiv:1109.2941v1

Article

(KIT-Theory)

Pure dephasing in flux qubits due to flux noise with spectral density scaling as 1/fα

S. M. Anton, C. Müller, J. S. Birenbaum, S. R. O'Kelley, A. D. Fefferman, D. S. Golubev, G. C. Hilton, H.-M. Cho, K. D. Irwin, F. C. Wellstood, G. Schön, A. Shnirman, and J. Clarke

2011 arXiv:1111.7272

Article

(KIT-Theory)

Geometric quantum gates with superconducting qubits

I. Kamleitner, P. Solinas, C. Müller, A. Shnirman, M. Möttönen

2011 Phys. Rev. B 83, 214518 (2011), DOI: 10.1103/PhysRevB.83.214518

Article

(KIT-Theory)

Strong coupling of spin qubits to a transmission line resonator

Pei-Qing Jin, M. Marthaler, A. Shnirman, G. Schön 2011 arXiv:1112.0869

Article

(KIT-Theory)

Sub-Poissonian photon statistics in a strongly coupled single-qubit laser

M. Marthaler, P. Q. Jin, J. Leppäkangas, and G. Schön

2011 to be published in Journal of Physics: Conference Series, Proceeding LT26, Beijing 2011

Article

(KIT-Theory)

Charge transport through ultrasmall single and double Josephson junctions coupled to resonant modes of the electromagnetic environment

Yu. A. Pashkin, H. Im, J. Leppäkangas, T. F. Li, O. Astafiev, A. A. Abdumalikov, E. Thuneberg, and J. S. Tsai

2011 Phys. Rev. B 83, 020502(R) (2011); DOI: 10.1103/PhysRevB.83.020502

Article

(KIT-Theory)

Lasing and transport in a quantum-dot resonator circuit

P. Q. Jin, M. Marthaler, J. H. Cole, A. Shnirman, G. Schön

2011 Phys. Rev. B 84, 035322 (2011); DOI: 10.1103/PhysRevB.84.035322

Article

(KIT-Theory)

Correlation between lasing and transport properties in a quantum dot-resonator system

P. Q. Jin, M. Marthaler, J. H. Cole, M. Köpke, J. Weis, A. Shnirman, and G. Schön


Article

(KIT-Theory)

Emission characteristics of laser-driven dissipative coupled-cavity systems

M. Knap, E. Arrigoni, W. von der Linden, J. H. Cole

2011 Phys. Rev. A 83, 023821 (2011); DOI: 10.1103/PhysRevA.83.023821

Article

(KIT-Theory)

Quantum heating of a parametrically modulated oscillator: Spectral signatures

M. I. Dykman, M. Marthaler, V. Peano

2011 Phys. Rev. A 83, 052115 (2011); DOI: 10.1103/PhysRevA.83.052115

Article

(KIT-Theory)

The role of damping for the driven anharmonic quantum oscillator

L. Guo, M. Marthaler, S. André, and G. Schön


Article

(KIT-Theory)

Lasing without Inver-sion in Circuit Quantum Electrodynamics

M. Marthaler, Y. Utsumi, D. S. Golubev, A. Shnirman, G. Schön

2011 Phys. Rev. Lett. 107, 093901 (2011).

SOLID FP7 248629 2012-04-01



Article

(KIT-Theory)

Lasing, trapping states, and multistability in a circuit quantum electrodynamical analog of a single-atom injection maser

M. Marthaler, J. Leppakangas, J. H. Cole

2011 Phys. Rev. B 83, 180505(R) (2011); DOI: 10.1103/PhysRevB.83.180505

Article

(KIT-Theory / Exp)

Entangling microscopic defects via a macroscopic quantum shuttle

G. J. Grabovskij, P. Bushev, J. H. Cole, C. Müller, J. Lisenfeld, A. Lukashenko, A. V. Ustinov

2011 New J. Phys. 13, 063015 (2011); DOI: 10.1088/1367-2630/13/6/063015

Article (KIT-Exp)

Strain Tuning of Individual Atomic Tunneling Systems Detected by a Superconducting Qubit

G. Grabovskij, T. Peichl, J. Lisenfeld, G. Weiss, and A. V. Ustinov

2012 submitted to journal

Article (KIT-Exp)

Aluminum hard mask technique fort the fabrication of high quality submicron Nb/Al-AlOx/Nb Josephson junctions

Ch. Kaiser, J. M. Meckbach, K. S. Ilin, J. Lisenfeld, R. Schäfer, A. V. Ustinov, and M. Siegel

2011 Supercond. Sci. Technol. 24, 035005 (2011). DOI:10.1088/0953-2048/24/3/035005

Article (KIT-Exp)

Probing the TLS Density of States in Thin a-SiO Films using Superconducting Lumped Element Resonators

S. T. Skacel, Ch. Kaiser, S. Wu ̈nsch, H. Rotzinger, A. Lukashenko, M. Jerger, G. Weiss, M. Siegel, and A. V. Ustinov

2012 In preparation, to be published

Article (KIT-Exp)

Readout of a qubit array via a single transmission line

M. Jerger, S. Poletto, P. Macha, U. Hübner, A. Lukashenko, E. Il'ichev and A. V. Ustinov

EPL, 96, 40012 (2011)

DOI: 10.1209/0295-5075/96/40012

Article

(IPHT)

V. V. Roddatis, U. Hübner, B. I. Ivanov, E. Il’ichev, H.-G. Meyer, M. V. Koval’chuk, and A. L. Vasiliev

2011 J. Appl. Phys. 110, 123903 (2011)

Article

(IPHT)

B. I. Ivanov, M. Trgala, M. Grajcar, E. Il’ichev, and H.-G. Meyer,

2011 Rev., Sci., Instr., 82, 104705 (2011).

Article (KIT-Exp / IPHT)

Readout of a Qubit Array via a Single Transmission Line


2011 Europhys. Lett. 96, 40012 (2011). DOI:10.1209/0295-5075/96/40012

Article

(IPHT)

Readout of a qubit array via a single transmission line


EPL, 96, 40012 (2011)

DOI: 10.1209/0295-5075/96/40012

Article

(IPHT)

G. Oelsner, P. Macha, E. Il'ichev, U. Huebner, H.-G. Meyer, M. Grajcar, O. Astafiev

2012 In preparaton

Article

(CNRS-UJF)

Novel E-beam lithography technique for in-situ junction fabrication: the controlled undercut

F. Lecocq, C. Naud, I. M. Pop, Z. H. Peng, I. Matei, T. Crozes, T. Fournier, W. Guichard and O. Buisson.

2011 Nanotechnology 22 315302 (2011).

http://dx.doi.org/10.1088/0957-4484/22/31/315302

Article

(CNRS-UJF)

Quantum dynamics of a dc-SQUID coupled to an asymmetric Cooper pair transistor

A. Fay, W. Guichard, O. Buisson, F. W. J. Hekking.

2011 Phys. Rev. B 83, 184510 (2011)

10.1103/PhysRevB.83.184510

Article

(CNRS-UJF)

Nonlinear Coupling between the Two Oscillation Modes of a dc SQUID

F. Lecocq, J. Claudon, O. Buisson, and P. Milman

2011 Phys. Rev. Lett. 107, 197002 (2011)

10.1103/PhysRevLett.107.197002

SOLID FP7 248629 2012-04-01



Article

(CNRS-UJF)

Coherent Frequency Conversion in a Superconducting Artificial Atom with Two Internal Degrees of Freedom

F. Lecocq, I. M. Pop, I. Matei, E. Dumur, A. Feofanov, C. Naud, W. Guichard, O. Buisson,

2012 Phys. Rev. Lett. 108, 107001 (2012). 10.1103/PhysRevLett.108.107001

Article

(CNRS-UJF)

Quantum dynamics of a driven three-level Josephson-atom maser

N. Didier, Ya. M. Blanter, F.W.J. Hekking

2010 PRB 82, 214507 (2010).

10.1103/PhysRevB.82.214507

Article

(CNRS-UJF)

Quantum phase-slips in Josephson junction chains: effects of finite size and propagating modes

G. Rastelli, I. M. Pop, W. Guichard, F. W. J. Hekking

2012 arXiv:1201.0539

Article

(CNRS-UJF)

Macroscopic quantum tunneling in quartic and sextic potentials: application to a phase qubit

N. Didier, F. W. J. Hekking 2012

arXiv:1110.6311

Article

(CNRS-UJF)

Etching suspended

superconducting hybrid

junctions from a

multilayer

H. Q. Nguyen, L. M. A. Pascal,

Z. H. Peng, O. Buisson , B.

Gilles, C. Winkelmann , H.

Courtois.

2011 arXiv:1111.3541.

Article

(UNIBAS)

Ferromagnetic order of nuclear spins coupled to conduction electrons: a combined effect of the electron-electron and spin-orbit interactions,

R.A. Zak, D.L. Maslov, and D. Loss, 2011 arXiv:1112.4786

Article

(UNIBAS)

Absence of spontaneous magnetic order of lattice spins coupled to itinerant interacting electrons in one and two dimensions,

D. Loss, F.L. Pedrocchi, and A.J. Leggett, 2011 Phys. Rev. Lett. 107, 107201 (2011);

arXiv:1107.1223

Article

(UNIBAS)

Singlet-triplet splitting in double quantum dots due to spin orbit and hyperfine interactions,

D. Stepanenko, M. Rudner, B.I. Halperin, and D. Loss, 2011 arXiv:1112.1644 (submitted to PRB)

Article

(UNIBAS)

Crossed Andreev Reflection in Quantum Wires with Strong Spin-Orbit Interaction,

K. Sato, D. Loss, and Y. Tserkovnyak, 2011 arXiv:1109.6357

Article

(UNIBAS)

Long-distance spin-spin coupling via floating gates,

L. Trifunovic, O. Dial, M. Trif, J.R. Wootton, R. Abebe, A. Yacoby, and D. Loss

2012 Phys. Rev. X 2, 011006 (2012); arXiv:1110.1342

Article

(UNIBAS)

Localized end states in density modulated quantum wires and rings

S. Gangadharaiah, L. Trifunovic, and D. Loss, 2010 arXiv:1111.5273 (accepted for

publication in PRL)

SOLID FP7 248629 2012-04-01



Article

(UNIBAS)

Physical solutions of the Kitaev honeycomb model

F.L. Pedrocchi, S. Chesi, and D. Loss, 2011 Phys. Rev. B 84, 165414 (2011);

arXiv:1105.4573

Article

(UNIBAS)

Universal quantum computation with topological spin-chain networks

Y. Tserkovnyak and D. Loss, 2011 Phys. Rev. A 84, 032333 (2011); arXiv:1104.1210

Article

(UNIBAS)

Quantum-control approach to realising a Toffoli gate in circuit QED

V.M. Stojanovic, A. Fedorov, A. Wallraff, and C. Bruder,

2011 arXiv:1108.3442 , accepted in Phys. Rev. B

Article

(UNIBAS)

Greenberger-Horne-Zeilinger generation protocol for N superconducting transmon qubits capacitively coupled to a quantum bus

S. Aldana, Y.-D. Wang, and C. Bruder 2011 Phys. Rev. B 84, 134519 (2011). DOI:

10.1103/PhysRevB.84.134519

Article

(TUM)

Direct observation of a non-catalytic growth regime for GaAs nanowires

D. Rudolph, et al. 2011 Nano Letters 11, 3848 (2011) DOI: 10.1021/nl104265u

Article

(TUM)

Absence of vapor-liquid-solid growth during molecular beam epitaxy of self-induced InAs nanowires on Si

S. Hertenberger, et al. 2011 Appl. Phys. Lett. 98, 123114 (2011) DOI: 10.1063/1.3567496

Article

(TUM)

Observation and explanation of strong electrically tunable exciton g factors in composition engineered In(Ga)As quantum dots

V. Jovanov, et al. 2011 Phys. Rev. B 83, 161303 (2011)

DOI: 10.1103/PhysRevB.83.161303

Article

(TUM)

Direct observation of metastable hot trions in an individual quantum dot

V. Jovanov et al. 2011 Phys. Rev. B 84, 235321 (2011)

DOI: 10.1103/PhysRevB.84.235321

Article

(TUM)

Excited state quantum couplings and optical switching of an artificial molecule,

K. Müller et al. 2011 Phys. Rev. B 84, 081302 (2011)

DOI: 10.1103/PhysRevB.84.081302

Article

(TUM)

Coplanar stripline antenna design for optically detected magnetic resonance on semiconductor quantum dots

F. Klotz et al., 2011 Rev. Sci. Instrum. 82, 074707 (2011)

DOI: 10.1063/1.3608110

Article

(TUM)

Electrical control of the exciton-biexciton splitting in self-assembled InGaAs Quantum dots,

M. Kaniber et al. 2011 Nanotechnology 22, 325202, (2011)

DOI:10.1088/0957-4484/22/32/325202

Article

(TUM)

Nonresonant feeding of photonic crystal nanocavity modes by quantum dots

A. Laucht et al. 2011 J. Appl .Phys. 109, 102404, (2011)

DOI: 10.1063/1.3576137

Article Electrical control of ultrafast intra-molecular

K. Müller et al. 2011 arXiv: 1111.3137; accepted for Phys. Rev Lett. (2012)

SOLID FP7 248629 2012-04-01



(TUM) dynamics in an artificial molecule

Article

(TUM)

A Waveguide-Coupled On-Chip Single Photon Source

A. Laucht, et al. 2012 arXiv: 1201.5153; accepted for Phys. Rev. X (2012)

Article

(TUM)

Highly Non-linear Excitonic Zeeman Spin-Splitting in Composition-Engineered Artificial Atoms,

V. Jovanov et al. 2011 arXiv:1112.2585; accepted for Phys. Rev. B (2012)

Article

(USTUTT)

Electric-Field Sensing Using Single Diamond Spins

F. Dolde, H. Fedder, M. W. Doherty, T. Nobauer, F. Rempp, G. Balasubramanian, T. Wolf, J. Wrachtrup, et al.

2011 Nature Physics 7, 459 (2011) DOI:10.1038/nphys1969

Article

(USTUTT/ Australia)

High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond

L.T. Hall, J. Wrachtrup, L. Hollenberg et al., 2012 Nature Scientific Reports (accepted 7th

of February 2012)

Article

(USTUTT/ Australia)

Quantum Measurement and Orientation Tracking of Fluorescent Nanodiamonds inside Living Cells

L.P. McGuinness, Y. Yan, A. Stacey, D. A. Simpson, L. T. Hall, D. Maclaurin, S. Prawer, J. Wrachtrup, et al.

2011 Nature Nanotechnology 6, 358 (2011)

DOI:10.1038/nnano.2011.64

Article

(USTUTT)

Creation of Colour Centres in Diamond by Collimated Ion-Implantation through Nano-Channels in Mica

S.Pezzagna, D. Rogalla, H. W. Becker, I. Jakobi, F. Dolde, B. Naydenov, J. Wrachtrup, et al.

2011

Physica Status Solidi a -Applications and Materials Science 208, 2017 (2011)

DOI: 10.1002/pssa.201100455

Article

(USTUTT)

Highly Efficient FRET from a Single Nitrogen-Vacancy Center in Nanodiamonds to a Single Organic Molecule

J.Tisler, R. Reuter, A. Lammle, F. Jelezko, G. Balasubramanian, P. R. Hemmer, F. Reinhard, and J. Wrachtrup.

2011 ACS Nano 5, 7893 (2011)

DOI: 10.1021/nn2021259

Article

(USTUTT)

Dark States of Single Nitrogen-Vacancy Centers in Diamond Unraveled by Single Shot NMR

G. Waldherr, J. Beck, M. Steiner, P. Neumann, A. Gali, Th Frauenheim, F. Jelezko, and J. Wrachtrup.

2011 Physical Review Letters 106, 157601 (2011)


Article

(USTUTT)

Violation of a Temporal Bell Inequality for Single Spins in a Diamond Defect Center

G. Waldherr, P. Neumann, S. F. Huelga, F. Jelezko, and J. Wrachtrup

2011 Physical Review Letters 107, 090401 (2011)


Article

(USTUTT)

High-dynamic-range magnetometry with a single nuclear spin in diamond

G. Waldherr, J.Beck, P. Neumann, J. Wrachtrup et al. 2011 Nature Nanotechnology 7, 105 (2012)

DOI:10.1038/nnano.2011.224

Article

(SNS)

High fidelity quantum driving

M. G. Bason, M. Viteau, N. Malossi, P. Huillery, E. Arimondo, D. Ciampini, R. Fazio, V. Giovannetti, R. Mannella, and O. Morsch

2012 Nature Physics 8, 147 (2012); DOI:10.1038/nphys2170

Article

(SNS)

A Josephson quantum electron pump

F. Giazotto, P. Spathis, S. Roddaro, S. Biswas, F. Taddei, M. Governale and L. Sorba

2011 Nature Physics, 7, 857 (2011) DOI:10.1038/nphys2053

Article

(SNS)

Persistent spin oscillations in spin-orbit coupled superconductors

Amit Agarwal, Marco Polini, Rosario Fazio, and G. Vignale 2011 Phys. Rev. Lett. 107, 077004 (2011);

DOI 10.1103/PhysRevLett.107.077004

SOLID FP7 248629 2012-04-01



Article

(SNS)

Controlled coupling of spin-resolved quantum Hall edge states

B. Karmakar, D. Venturelli, L. Chirolli, F. Taddei, V. Giovannetti, R. Fazio, S. Roddaro, G. Biasiol, L. Sorba, V. Pellegrini, and F. Beltram

2011 Phys. Rev. Lett. 107, 236804 (2011); DOI 10.1103/PhysRevLett.107.236804

Article

(SNS)

Detecting phonon blockade with photons

Nicolas Didier, Stefano Pugnetti, Yaroslav M. Blanter, and Rosario Fazio

2011 Phys. Rev. B 84, 054503 (2011); DOI DOI: 10.1103/PhysRevB.84.054503

Article

(SNS)

Speeding up critical system dynamics through optimized evolution

Tommaso Caneva, Tommaso Calarco, Rosario Fazio, Giuseppe E. Santoro, and Simone Montangero

2011 Phys. Rev. A 84, 012312 (2011); DOI 10.1103/PhysRevA.84.012312

Article

(SNS)

Floquet theory of Cooper pair pumping

Angelo Russomanno, Stefano Pugnetti, Valentina Brosco, and Rosario Fazio

2011 Phys. Rev. B 83, 214508 (2011); DOI:

10.1103/PhysRevB.83.214508

Article

(SNS)

Spin-supersolid phase in Heisenberg chains: a characterization via Matrix Product States with periodic boundary conditions

Davide Rossini, Vittorio Giovannetti, and Rosario Fazio 2011 Phys. Rev. B 83, 140411 (2011) ; DOI:

10.1103/PhysRevB.83.140411

Article

(SNS)

Spatially-resolved analysis of edge-channel equilibration in quantum Hall circuits

Nicola Paradiso, Stefan Heun, Stefano Roddaro, Davide Venturelli, Fabio Taddei, Vittorio Giovannetti, Rosario Fazio, Giorgio Biasiol, Lucia Sorba, and Fabio Beltram

2011 Phys. Rev. B 83, 155305 (2011) ; DOI:

10.1103/PhysRevB.83.155305

Article

(SNS)

Time-bin entanglement of quasi-particles in semiconductor devices

Luca Chirolli, Vittorio Giovannetti, Rosario Fazio, Valerio Scarani

2011 Phys. Rev. B 84, 195307 (2011); DOI:

10.1103/PhysRevB.84.195307

Article

(SNS)

Josephson current in a four terminal superconductor - exciton condensate - superconductor system

Sebastiano Peotta, Marco Gibertini, Fabrizio Dolcini, Fabio Taddei, Marco Polini, L.B. Ioffe, Rosario Fazio, A.H. MacDonald

2011 Phys. Rev. B 84, 184528 (2011); DOI:

10.1103/PhysRevB.84.184528

Article

(SNS)

Edge channel mixing induced by potential steps in an integer quantum Hall system

D. Venturelli, V. Giovannetti, F. Taddei, R. Fazio, D. Feinberg, G. Usaj, and C.A. Balseiro

2011 Phys. Rev. B 83, 075315 (2011) ; DOI:

10.1103/PhysRevB.83.075315

Article

(SNS)

Stiffness in 1D Matrix Product States with periodic boundary conditions

Davide Rossini, Vittorio Giovannetti, Rosario Fazio 2011 J. Stat. Mech. (2011) P05021;

doi:10.1088/1742-5468/2011/05/P05021

Article

(SNS)

Robustness and Errors in Quantum Optimal Control

A. Negretti, R. Fazio, and T. Calarco 2011 J. Phys. B: At. Mol. Opt. Phys. 44,

154012 (2011)doi:10.1088/0953-4075/44/15/154012

Article

(SNS)

High fidelity quantum driving

M. G. Bason, M. Viteau, N. Malossi, P. Huillery, E. Arimondo, D. Ciampini, R. Fazio, V. Giovannetti, R. Mannella, and O. Morsch

2012 Nature Physics 8, 147 (2012); DOI:10.1038/nphys2170

Article

(UPV/EHU)

The nonrelativistic limit of the Majorana equation and its quantum simulation in trapped ions

L. Lamata, J. Casanova, I. L. Egusquiza, and E. Solano 2012 Phys. Scr. T147, 014017 (2012)

DOI:10.1088/0031-8949/2012/T147/014017

Article

(UPV/EHU)

Validity of resonant two-qubit gates in the ultrastrong coupling regime of circuit QED

Y. M. Wang, D. Ballester, G. Romero, V. Scarani, and E. Solano

2012 Phys. Scr. T147, 014031 (2012)

DOI:10.1088/0031-8949/2012/T147/014031

SOLID FP7 248629 2012-04-01



Article

(UPV/EHU)

Quantum simulation of the ultrastrong coupling dynamics in circuit QED

D. Ballester, G. Romero, J. J. García-Ripoll, F. Deppe, and E. Solano

2012 To be published in Physical Review X (2012).

Article

(UPV/EHU)

Ultrafast Quantum Gates in Circuit QED

G. Romero, D. Ballester, Y. M. Wang, V. Scarani, and E. Solano

2012 Phys. Rev. Lett. 108, 120501 (2012)


Article

(UPV/EHU)

Probing Biological Light-Harvesting Phenomena by Optical Cavities

F. Caruso, S. K. Saikin, E. Solano, S. F. Huelga, A. Aspuru-Guzik, and M. B. Plenio

2012 Phys. Rev. B 85, 125424 (2012)

DOI: 10.1103/PhysRevB.85.125424

Article

(UPV/EHU)

Multipartite entanglement generation assisted by inhomogeneous coupling

C. E. López, F. Lastra, G. Romero, E. Solano, and J. C. Retamal

2012 Phys. Rev. A 85, 032319 (2012)

DOI: 10.1103/PhysRevA.85.032319

Article

(UPV/EHU)

Quantum tomography in position and momentum space

J. Casanova, C. E. López, J. J. García-Ripoll, C. F. Roos, and E. Solano,

2011 submitted to Physical Review A (2012);

arXiv:1107.2068

Article

(UPV/EHU)

Selection rules in a strongly coupled qubit-resonant system

T. Niemczyk, F. Deppe, E. P. Menzel, M. J. Schwarz, H. Huebl, F. Hocke, M. Häberlein, M. Danner, E. Hoffmann, A. Baust, E. Solano, J. J. García-Ripoll, A. Marx, and R. Gross

2011 To be published in Phys. Rev. B (2011)

Conference (invited talk) (Chalmers)

Toward classical-quantum hybrid information processing

G. Wendin 2011 Quantum Simulations Workshop, Benasque, Spain, Feb 28 - March 1, 2011

Conference (Invited talk) (CEA)

Strong Coupling of a Spin Ensemble to a Superconducting Resonator

P. Bertet March 2011

DPG meeting, Dresden

Invited talk

(CEA)

Hybrid Quantum Circuit with a Superconducting Qubit coupled to a Spin Ensemble

P. Bertet June 2011

Waterloo University


Nonlinear circuit QED : coupling a qubit to an anharmonic resonator

P. Bertet March 2011

APS March meeting, Dallas


Strong coupling of a spin ensemble to a superconducting resonator

D. Vion Jan. 2011

International Symposium on Nanoscale Transport and Technology (ISNTT2011)

Invited talk (CEA)

Strong Coupling of a Spin Ensemble to a Superconducting Resonator

D. Vion May

2011

Ulm University


Coupling of a spin ensemble to a superconducting qubit through a resonator

D. Vion July 2011

Frontiers of Quantum and Mesoscopic Thermodynamics 2011 (FQMT'11) , Prague


Towards hybrid quantum computing: coupling a spin ensemble to a superconducting qubit

D. Vion Oct.

2011

Quantum Spintronics

Sardegna (Italy), Oct 2011

SOLID FP7 248629 2012-04-01



through a resonator


Electrical circuits for quantum physics and quantum information

D. Esteve March 2011

Quantum Mesoscopic Physics

Rencontres de Moriond, la Thuile (Italy)


Operating an elementary quantum processor

D. Esteve Dec 2011

Workshop GDR-IQFA,

Inst. Henri Poincaré, Paris

Conference (Invited talk) (TUD)

Integrated superconducting nanowire detectors for quantum plasmonics

V.Zwiller 2011 SPIE conference, Prague, Czech Republic, 18 April 2011


Putting superconducting nanowire detectors to use

V.Zwiller 2011 Advanced photon counting techniques conference, Orlando, USA, 28 April 2011


InP based quantum light emitting diodes

V.Zwiller 2011 IPRM, Berlin, Germany, 22 May 2011


Coupling single quantum dots to atomic vapors

V.Zwiller 2011 Quantum control of Solid State systems workshop, Princeton University, USA, 4 November 2011


Vision talk on Coherent NanoSystems

L.P. Kouwenhoven 2011 Future Symposium “Plenty of Room in the Middle: NanoScience- The Next 50 Years” at CalTech Pasadena, USA; 15 January 2011; Invited talk available at http://kni.caltech.edu/middle/


Quantum Opto-Electronics in Semiconductor Nanowires

L.P. Kouwenhoven 2011

Moriond Workshop 2011 on “Quantum Mesoscopic Physics” 14-18 March, 2011


Quantum Opto-Electronics in Semiconductor Nanowires


NanoSpain2011 Conference, Bilbao, 11-15 April. 2011


Engineering a nanowire cradle for Majorana Fermions


Microsoft Station Q, California, 17-19 June 2011


Particle Physics on a Chip – The search for Majorana Fermions


International Conference on Low Temperature Physics, LT26 Beijing, 10-17 August 2011


Induced Superconductivity in Semiconductor Nanowires


Workshop on Superconducting Hybrids, Villard de Lance (France), 6-10 September 2011


That’s a one centimeter step for man, one giant leap for mankind.

L.P. Kouwenhoven 2011 TEDxDelft, 18 minute presentation


Physics of hybrid superconducting-semiconducting nanowires

L.P. Kouwenhoven 2011 Microsoft Station Q, California, 1-4 December 2011


Control and coherence of the optical transition of single defect centers in diamond

R. Hanson 2011

SPIE Photonics West, San Francisco, 26 January 2011


Control of single-spin decoherence by dynamical decoupling and spin bath

R. Hanson 2011

March Meeting of the American Physical Society, 25 March 2011

SOLID FP7 248629 2012-04-01



manipulation


Quantum measurement and coherence protection of spins in diamond

R. Hanson 2011

The 62nd Diamond Conference, Warwick (UK), 5 July 2011


Decoherence protection of passiveand active solid-state spin qubits

R. Hanson 2011

QIPC2011: Quantum Information Processing and Communication International Conference, Zurich (Switzerland), 6 September 2011


Initialization and single-shot readout of a quantum register (hot topic presentation)

R. Hanson 2011

QIPC2011: Quantum Information Processing and Communication International Conference, Zurich (Switzerland), 7 September 2011


Robust superconducting circuits for quantum computing

L. DiCarlo 2011 NanoCTM Meeting in Lake Balaton, Hungary, June 16, 2011


It needn’t be nano to be quantum: quantum computing with macroscopic circuits

L. DiCarlo 2011 Biannual Casimir Symposium, Delft University of Technology, The Netherlands, May 26, 2011

Conference (invited talk) (ETHZ)

Dispersive multi-mode mediated qubit coupling in circuit QED

S. Filipp 2011 Quantum Simulations Workshop, Benasque, Spain, Feb 28 - March 1, 2011

Conference (contributed talk) (ETHZ)

Dark States of Cavity Coupled Qubits

S. Filipp, A. F. van Loo, QUDEV-Team, and A. Wallraff 2011 APS March Meeting, Dallas, USA,

March 21 - 25, 2011


Quantum Science and Technology with Superconducting Electronic Circuits

A. Wallraff 2011 International Conference "Quantum Technology", Akademie der Naturforscher Leopoldina, German Museum, Munich, Germany, May 8 - 10, 2011


Quantum Optics and Quantum Computing with Superconducting Circuits

A. Wallraff 2011 Quantum Repeater Status Seminar 2011, Bad Honnef, Germany, June 20 - 22, 2011


Benchmarking a Teleportation Circuit realized in Circuit QED

A. Fedorov 2011 The 1st International Conference on Quantum Technologies, Moscow, July 11-17, 2011


Distributing Quantum Information with Microwave Resonators in Circuit QED

S. Filipp 2011 4th Workshop on the Physics and

Applications of Superconducting Microresonators, Grenoble, France, July 28 - 29, 2011


Exploring the Quantum Physics of Light with Micro- and Nanoelectronic Circuits

A. Wallraff 2011 Nanosciences: From molecular systems to functional materials, Venice International University (VIU), Venice, Italy, Sept. 19 - 23, 2011


Photons, Qubits and Computers - A Quantum Mechanics Lab on a Chip

A. Wallraff 2011 Condensed Matter and Materials Physics Conference (CMMP11), Manchester, UK, Dec. 13-15, 2011


Overview of Activities at ETH Zurich

A. Wallraff 2012 SOLID Topical Workshop on Josephson Junction Circuits: Coherence, Control, Correction, and Communication, Delft University of Technology, Delft, Netherlands, Jan. 16 - 17, 2012

Conference Hybrid Quantum Systems using

A. Wallraff 2012 SOLID Topical Workshop on Josephson Junction Circuits: Coherence, Control,

SOLID FP7 248629 2012-04-01



(invited talk) (ETHZ)

Microwave Frequency On-Chip Resonators as a Coupling Bus

Correction, and Communication, Delft University of Technology, Delft, Netherlands, Jan. 16 - 17, 2012


Benchmarking a Teleportation Protocol with Superconducting Circuits

A. Wallraff 2012 SOLID Topical Workshop on Josephson Junction Circuits: Coherence, Control, Correction, and Communication, Delft University of Technology, Delft, Netherlands, Jan. 16 - 17, 2012

Conference (invited Talk) (ETHZ)

Implementation of the Toffoli gate in circuit QED architecture

A. Fedorov, L. Steffen, M. Baur, M. P. da Silva, and A. Wallraff

2012 SOLID Topical Workshop on Josephson Junction Circuits: Coherence, Control, Correction, and Communication, Delft University of Technology, Delft, Netherlands, Jan. 16 - 17, 2012

Conference (contributed talk) (ETHZ)

Coupling a double quantum dot to a microwave resonator

P. Leek, T. Frey, M. Beck, T. Ihn, A. Wallraff, and K. Ensslin 2011 Quantum Information Processing and

Communication (QIPC) 2011, International conference at ETH Zurich, Zurich, Switzerland, Sept. 5 - 9, 2011

Conference (Invited talk)

(KIT-Theory)

Quantum State Engineering with Josephson Junctions

G. Schön 2011 Plenary talk at 26th Int. Conference on Low Temperature Physics, Beijing, China, August 10-17, 2011


(KIT-Theory)

Lasing and Transport in a Quantum Dot - Resonator Circuit

G. Schön 2011 Conference on Frontiers of Quantum and Mesoscopic Thermodynamics, Prague, Czech Republic, July 25-30, 2011


(KIT-Theory)

Lasing and Transport in Circuit QED G. Schön 2011 Int. Conference on Quantum Technologies,

Moscow, Russia, July 13-17, 2011


(KIT-Exp)

Incoherent microwave-induced resistive states in Josephson junctions

A.V. Ustinov 2011 "Terahertz Superconducting Electronics", Blaubeuren, Germany, October 16-19, 2011


(KIT-Exp)

Superconducting artificial atoms as building blocks for quantum metamaterials

A.V. Ustinov 2011 Int. Conference "Metamaterials 2011”, Barcelona, Spain, October 10-15, 2011


(KIT-Exp)

Scaling-up architectures for superconducting quantum circuits

A.V. Ustinov 2011 Int. Humboldt College and Workshop Nano-2011, Kishinev, Moldova, 6-9 October, 2011


(KIT-Exp)

Exploring two-level defects in amorphous oxide barriers of Josephson junctions

A.V. Ustinov 2011 Int. Workshop on Complex Phenomena

in Superconductivity and Magnetism, Hardangerfjord, Norway, August 29 - September 3, 2011


(KIT-Exp)

Josephson Plasmons in Superconducting Metamaterials

A.V. Ustinov 2011 Int. Conference “NanoMeta 2011 - the

3rd International Topical Meeting on Nanophotonics and Metamaterials”, Seefeld, Austria, 3-6 January, 2011

Conference (Invited talk) (CNRS-UJF)

Coherent Frequency Conversion in a Superconducting Artificial Atom with Two Internal Degrees of Freedom

F. Lecocq

2011 Moriond 2011, Quantum Mesoscopic Physics, La Thuile, Aosta valley (Italy), March 13 – 20, 2011.

Conference (CNRS-UJF)

Coherent Frequency Conversion in a Superconducting Artificial Atom with

F. Lecocq

2011 March Meeting 2011, March 2011.

SOLID FP7 248629 2012-04-01



Two Internal Degrees of Freedom

Conference (Invited talk) (CNRS)

Quantum dynamics of Josephson junction based circuits

O. Buisson

2011 Taiwan-France joint school on Quantum Information Science & Workshop on Quantum Measurement, Taiwan, mai 2011.


A superconducting artificial atom with two internal degrees of freedom

O. Buisson

2011 Workshop " Quantum machines" Les Houches. July 2011.


Non linear coupling in an artificial atom

O. Buisson

2011 Kryo 2011, Autrans, October 2011.


A superconducting artificial atom with two internal degrees of freedom

O. Buisson

2011 Conference Dautreppe on Superconductivity, Grenoble Novembre 2011.


Phase-charge duality in Josephson junction chains

F. Hekking 2011 Rencontres de Moriond 2011 Quantum Mesoscopic Physics, La Thuile, Aosta valley (Italy), March 13 – 20, 2011.


Quantum dynamics of superconducting nanojunctions

F. Hekking 2011 XXIème Congrès général de la Société Française de Physique, July 4 – 8, 2011, Bordeaux (France).


Introduction to superconducting junctions and proximity effect

F. Hekking 2011 lecture during Les défis actuels de la supraconductivité, Séminaire Daniel Dautreppe 2011, Grenoble (France), November 21 – 25, 2011.


Phase-charge duality in Josephson junction chains

F. Hekking 2011 IPS – SFP Joint Meeting 2012, January 16 – 19 2012, Nanyang Executive Center, Singapore (Singapore)


Circuit approach to photonic heat transport

F. Hekking 2011

Frontiers of Quantum and MesoscopicThermodynamics July 25-30, 2011, Prague -Czech Republic

Conference (Invited talk) (SNS)

R. Fazio 2011

Workshop on New Trends in Quantum Dynamics and Quantum Entanglement - ICTP Trieste, Feb 2011


R. Fazio 2011

Quantum Information Processing and Applications - HRI- Allahabad, India, Feb 2011


R. Fazio 2011

Quantum science and technologies - Rovereto, May 2011


R. Fazio 2011

Entanglement, Quantum information and the Quantum to classical transition - Rome May 2011


R. Fazio 2011

CFN Summer School 2011 on NANO-ELECTRONICS - Bad Herrenalb, Sept 2011


R. Fazio 2011

Quantum to Classical Crossover in Mechanical Systems - Leiden Oct 2011


R. Fazio 2011

Engineering and Control of Quantum System - Dresden Oct 2011

SOLID FP7 248629 2012-04-01



(SNS)


F. Taddei 2011

Workshop ``Nonlinear spin and charge transport through nanoscopic systems'', IFISC, Palma di Maiorca (Spain), June 2011


F. Taddei 2011

Frontiers of quantum and mesoscopic thermodynamics, FQMT'11', Prague, July 2011


D. Rossini 2011

Many-Body Quantum Dynamics in Closed Systems: challenges and applications, Barcelona, sept 2011


D. Rossini 2011

Problemi Attuali di Fisica Teorica, Vietri Sul Mare, Italy, 2011 April 15 – 20

Conference (Contributed talk) (SNS)

D. Rossini 2011

Quantum simulations, Benasque , March 2011

Conference (Invited talk) (UPV/EHU)

Central European Workshop on Quantum Optics (CEWQO)

E. Solano 2011 Madrid, Spain (June 2011).


Invited talk at “Jornada de Información Cuántica”, Fundación Ramón Areces,

E. Solano 2011 Madrid, Spain (November 2011).


Invited talk at "Quantum Information, Measurement and Control",

E. Solano 2011 INRIA, Versailles, France (December 2011)


Invited talk at SOLID Workshop

D. Ballester 2012 Grenoble, France, 20-23 Feb 2012

Conference (Poster) (TUD)

Quantum measurement of superconducting qubits in circuit Q3D

D. Ristè, J. van Leeuwen, M. Shakori, L. DiCarlo 2012 2012 FOM Veldhoven Meeting, The

Netherlands, January 17-18, 2012

Conference (poster) (ETHZ)

Quantum optics experiments with 2D and 3D microwave cavities

J. M. Fink 2011 Micro and macro-cavities in classical and non-classical light, Physikzentrum Bad Honnef, Germany, Sep 30 - Oct 3, 2011


Hybrid Cavity QED with Rydberg Atoms and Circuits

S. Filipp, T. Thiele, C. Gross, A. Wallraff, S. Hogan, P. Allmendinger, J. Agner, and F. Merkt



Implementation of a Toffoli Gate with Superconducting Circuits

L. Steffen, A. Fedorov, M. Baur, A. Wallraff



Symmetry-selective Rabi oscillations and observation of subradiance in circuit QED

S. Filipp, A. F. van Loo, M. Baur, L. Steffen, and A. Wallraff

2011 Quantum Information Processing and Communication (QIPC) 2011, International conference at ETH Zurich, Zurich, Switzerland, Sept. 5 - 9, 2011


Quantum process tomography of entangling gates in circuit QED

L. Steffen, M. Baur, A. Fedorov, K. Pakrouski, and A. Wallraff


SOLID FP7 248629 2012-04-01




Integration of quantum dots with superconducting microwave circuits

T. Frey, P. J. Leek, M. Beck, K. Ensslin, A. Wallraff, and T. Ihn



Generation of multi-qubit entanglement in circuit QED architecture

A. Fedorov, M. Baur, L. Steffen, K. Pakrouski, and A. Wallraff


PhD thesis (KIT)

Dispersive readout scheme for a Josephson phase qubit

T. Wirth 2011 Ph. D. Thesis (March, 2011)

PhD thesis (KIT)

Influence of mechanical deformation on atomic tunneling systems – studied using a Josephson phase qubit

T. Peichl 2011 Ph. D. Thesis (February, 2011)

Phd thesis

(CNRS)

Dynamique quantique dans un dcSQUID: du qubit de phase à l’oscillateur quantique bidimensionnel

F. Lecocq 2011 PhD thesis of Joseph Fourier University

(2011).

MSc thesis (TUD) 3-D superconducting

cavities for circuit quantum electro-dynamics

J. van Leeuwen 2011 Supervised by L. DiCarlo, TU Delft

MSc thesis (TUD) Phase-Slip qubit

coupled to a LC-resonator

Alexander Bilmes

2011 Master Research Reports

MSc thesis (TUD)

Kerr effects in a dc SQUID

Etienne Dumur 2011 Master Research Reports

MSc thesis (KIT) Three level systems and

decoherence”

N. Vogt 2011

Thesis, (February, 2011)

MSc thesis (KIT) Two qubits as a

decoherence probe of the environment

J. Jeske 2011 Master Thesis )2011)

MSc thesis (KIT) Relaxation of a two-

level system under the influence of a phase qubit

D. Mischek 2011 Master Thesis (June, 2011)

MSc thesis (KIT) Relaxation of a two-

level system under the influence of a phase qubit

D. Mischek 2011 Master Thesis (June, 2011)

MSc thesis (KIT) Decoherence by spins at

the surface of metals

P. Schad Master Thesis (July, 2011)

MSc thesis (KIT) Tomography and

control of phase qubits”

P. Skwierawski Master Thesis (February, 2011)

MSc thesis (KIT) Investigation of

dielectric losses in amorphous thin films

S. Skacel Master Thesis (February, 2011)

MSc thesis (SNS)

Circuit-QED in the ultra-strong regime

G. Micchi 2012 Supervised by R. Fazio

SOLID FP7 248629 2012-04-01



Lectures

(CEA)

Introduction to superconducting qubits

Patrice Bertet June2011

11th Canadian Summer School on Quantum Information http://www.crm.umontreal.ca/QI11/index_e.php

Lectures (CEA)

Readout of superconducting quantum bits

Daniel Esteve July 2011

Les Houches School Quantum machines & control of engineered quantum systems, Les Houches

http://physinfo.fr/houches/program.html

Lectures (CEA)

Superconducting qubit architectures for quantum information

Daniel Esteve Nov 2011

QIP school on Quantum Information, Measurement and Control

INRIA, Paris-Roquencourt

Talk (Seminar) (TUD)

Quantum optics with nanowires and quantum dots’

V. Zwiller 2011 11 March seminar at Hokkaido University


Nano-optics with single photons’

V. Zwiller 2011 15 September Colloquium at KTH Stockholm, Sweden


Nano-optics with single photons

V. Zwiller 2011 16 September seminar at Niels Bohr Institute, Copenhagen, Denmark


Particle Physics on a Chip

L.P. Kouwenhoven 2011 7 February Colloquium at ICFO – The Institute of Photonic Sciences, Barcelona


Particle Physics on a Chip – The search for Majorana Fermions

L.P. Kouwenhoven 2011 2 November Colloquium at ETH Zurich


Dynamical decoupling of single spins: demonstration and applications

R.Hanson 2011 Seminar at California NanoSystems Institute at UCSB, Santa Barbara (USA),28 January 2011


Quantum measurement and coherence protection of single spins in diamond

R.Hanson 2011 Seminar at CEA-Saclay, Paris, 27 April 2011


Engineering multi-particle entanglement in superconducting quantum circuits

L. DiCarlo 2011 Condensed Matter Seminar at University of Basel, 30 May 2011


Multi-qubit circuit Q3D L. DiCarlo 2011 Seminar at CEA-Saclay, Paris, 12 October 2011

Lecture (ETHZ)

Circuit Quantum Electrodynamics

A. Wallraff 2011 NanoResonance 2011, Heinrich Fabri Haus, Blaubeuren, Germany, Nov. 2 - 6, 2011

Talk (seminar) (ETHZ)

Photons, Qubits and Computers - Constructing Quantum Machines on a Chip (seminar talk)

A. Wallraff 2011 Physikalisches Kolloquium, invited by Prof. Gernot Guentherodt, RWTH Aachen, Aachen, Germany, November 28, 2011


Circuit Quantum Electrodynamics: Photons, Superconducting Qubits and Atoms on a chip

S. Filipp 2011 ‘Cold Atoms' - Group seminar, invited by Lucia Hackermueller, University of Nottingham, U.K., December 7, 2011


Circuit QED for Quantum Control and Computing

A. Fedorov 2011 Group seminar, invited by K. Ishibashi, RIKEN, Wako, Japan, August 9, 2011

SOLID FP7 248629 2012-04-01



Talk (Seminar) (CNRS-UJF)

“Non linear coupling in an artificial atom”,

Florent Lecocq

2011 Boulder, USA

Talk (Seminar)

(CNRS-UJF)

“Non linear coupling in an artificial atom”,

Florent Lecocq

2011 IBM, YorkTown, USA

Talk (Seminar) (SNS)

Simulating the dynamics of multi-qubit systems

D. Rossini 2011 DMFCI - Catania invited by Dr. L. Amico July 12-15

Talk (Seminar)

(UPV/EHU)

Enrique Solano 2011 University "Johannes Gutenberg", Mainz, Germany (March 2011

Talk (Seminar)

(UPV/EHU)

Enrique Solano 2011 Harvard University, Cambridge, MA, USA (April 2011).

Talk (Seminar)

(UPV/EHU)

Enrique Solano 2011 Oxford University, Oxford, UK (August 2011).

Talk (Seminar)

(UPV/EHU)

Enrique Solano 2011 Bristol University, Bristol, UK (August 2011).

Talk (Seminar)

(UPV/EHU)

Enrique Solano 2011 Imperial College, London, UK (August 2011).

Lecture (ETHZ)

Quantum optics with superconducting circuits

A. Wallraff 2011 CFN Summer School 2011 on NANO-ELECTRONICS, Bad Herrenalb, Germany, Sept. 11 - 14, 2011

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