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Kilian Singer Quantum information processing with ions and towards scalable quantum information processing with solid state systems http://www.quantenbit.de Collaborations: P. Zahariev, P. Ivanov, N. Vitanov F. Schmidt-Kaler, U. Poschinger, A. Walther, S. Dawkins Implantation: F.Jelezko, B. Naydenov (Ulm), J. Wrachtrup (Stutt.), J. Meijer, S. Pezzagna (Bochum), S. Hell(Göttingen)

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Page 1: Ldb Convergenze Parallele_11

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Kilian Singer

Quantum information processing with ions and towards scalable quantum information processing with solid state systems

http://www.quantenbit.de

Collaborations: P. Zahariev, P. Ivanov, N. Vitanov F. Schmidt-Kaler, U. Poschinger, A. Walther, S. Dawkins Implantation: F.Jelezko, B. Naydenov (Ulm), J. Wrachtrup (Stutt.), J. Meijer, S. Pezzagna (Bochum), S. Hell(Göttingen)

Page 2: Ldb Convergenze Parallele_11

Moving ions

• out of the trap for ion implantation connecting solid state quantum systems

• within the trap for quantum information processing

• with heat for the realization of a heat engine

• to investigate the Kibble-Zurek mechanism

Cold

Hot

Work

Page 3: Ldb Convergenze Parallele_11

Moving ions

• out of the trap for ion implantation connecting solid state quantum systems

• within the trap for quantum information processing

• with heat for the realization of a heat engine

• to investigate the Kibble-Zurek mechanism

Cold

Hot

Work

Page 4: Ldb Convergenze Parallele_11

Motivation: Scalable Quantum Computing with Nitrogen vacancy colour centers

[NV] color center

Wavelength 637 nm

Line width 24 MHz

Dipole moment 1×10-29 Cm

ms = +/-1

ms = 0

3E

3A

optical excitation 637nm

2.88GHz 0.3nm

J. Meijer et al., Appl. Phys. B 82, 321 (2006).

Page 5: Ldb Convergenze Parallele_11

Coupling through Dipolar Magnetic Interaction of the Electron Spins

10nm

2 NV interacting:

100kHz @ 10nm

P. Neumann, et al.,Nature Physics 6, 249 (2010)

Page 6: Ldb Convergenze Parallele_11

Future Visions for 2nd vw funding period

Page 7: Ldb Convergenze Parallele_11

Motivation: Scalable Quantum Computing with Nitrogen vacancy colour centers

Universität Stuttgart, RUBION, Bochum

T=1.6 K 10 µm

1 NV

2 NV

3 NV

2 MeV: spot size 300nm

Page 8: Ldb Convergenze Parallele_11

MV tandem accelerator

(Bochum)

kV nano-beam setup

(Bochum)

kV single laser

cooled ions

(Mainz)

300nm higher resolution 1nm

Ion Implantation

Kooperation: F.Jelezko, B. Naydenov (Ulm),J. Wrachtrup (Stutt.), J. Meijer, S. Pezzagna (Bochum),S. Hell, D. Wildanger (Göttingen)

Page 9: Ldb Convergenze Parallele_11
Page 10: Ldb Convergenze Parallele_11

+ Top-down method

+ Singly charged ions

+ Independent of doping atom

+ Low energies (<1keV)

+ Nm resolution (expected)

- 3 Hz throughput

Segmented Paul Trap as Perfect Point Source for Laser Cooled Ions

AFM tip

Segmented ion trap

Electrostatic

einzel-lens

Substrate

Translation stage

Page 11: Ldb Convergenze Parallele_11

9nm

Trap design

KS, U. Poschinger, M. Murphy, P. Ivanov, F. Ziesel, T. Calarco, F. Schmidt-Kaler, Rev. Mod. Phys. 82, 2609 (2010)

Trap modelling with Fast Multipole Method:

Page 12: Ldb Convergenze Parallele_11

9nm

Trap design

Alignment of trap chips to trap axis

Page 13: Ldb Convergenze Parallele_11

9nm

Trap design

Filter board

Page 14: Ldb Convergenze Parallele_11

Trap Design

• Fs-laser cut alumina (125µm thickness)

• 11 electrodes

• 1 mm distance between chips

• 1 MHz (ax.)/2 MHz (rad.)

Page 15: Ldb Convergenze Parallele_11

Motivation: Transport out of Trap for Deterministic High Resolution Ion Implantation

35V // 0V // 35V

Pote

ntial /

a.U

.

Axial position / a.U.

.

500V // 0V // 35V

Pote

ntial /

a.U

.

Axial position / a.U.

Dia

mond

Page 16: Ldb Convergenze Parallele_11

Ion Extraction

(-2kV)

Amp

Phase switch

Helical resonator

Page 17: Ldb Convergenze Parallele_11

01.08.2013 17

Automatic Extraction of Ions

Page 18: Ldb Convergenze Parallele_11

12,2 12,4 12,6 12,8 13,0 15,0 15,2 15,4 15,6

0,00

0,05

E

M d

ete

cto

r sig

na

l / a

.u.

time of flight / µs

dark ions

EM

dete

cto

r sig

nal [a

.U.]

Deterministic Extraction of Ions

Ca 40 +

88(3) % detected

independent

of ion or molecule species

Dark ions ( CaO ) +

W. Schnitzler, N. M. Linke, R. Fickler, J. Meijer, F. Schmidt-Kaler, K. Singer, PRL 102, 070501 (2009)

Page 19: Ldb Convergenze Parallele_11

Velocity Distribution

Velocity (m/s)

= 7 . 10

v

v -5

Factor of 4 improvement

Page 20: Ldb Convergenze Parallele_11

Aperture Scans

Deflector

Aperture

300µ

m

Dynode Ion Detector

Page 21: Ldb Convergenze Parallele_11

Verification of alignment

x-deflection voltage

y-d

eflection v

oltage

95% efficiency

Page 22: Ldb Convergenze Parallele_11

Lens design

Page 23: Ldb Convergenze Parallele_11

Determinstic single ion delivery with 5nm resolution

13 µm before lens

(7x improved)

Electr. deflector

Blade Position (nm)

Hitra

te

Dynode

Ion Detector Ion Ion lens

Translation stage

Knife edge

Eion=1.5keV

2 keV

5.1 ± 2.7nm

Ion lens

(1000x improved)

Results:

Setup:

Page 24: Ldb Convergenze Parallele_11

Agreement with simulations Spot Size @ 2mK

Page 25: Ldb Convergenze Parallele_11

Nitrogen loading with ion gun

• Loading rate typically 1 Nitrogen per 10s

• Extraction 1 per minute

• N2+ (Mass from flight time: 28.4 ± 0.5 AMU)

• Tests of loading Pr+ are in progress

• Narrow velocity distribution

Trigger-delay (s) Trigger-delay (s)

Flig

ht tim

e (

s)

Flig

ht tim

e (

s) N2

+ Ca+

Time of flight measurements

∆𝑣

𝑣= 2.5 10−5

Page 26: Ldb Convergenze Parallele_11

NV in-situ detection with Super-resolution microscope

1µm

Status:

• Singe NV identification

• Spatial resolution 100nm

Plan:

• In-situ annealing of NV

• Improving resolution to 10nm

• Integration of MW double-resonance

spectoscopy

Page 27: Ldb Convergenze Parallele_11

S. Pezzagna, B. Naydenov, F. Jelezko, J. Wrachtrup and J. Meijer, New J. Phys. 12 065017

(2010)

NV Yield versus implantation energy

NV Yield

Page 28: Ldb Convergenze Parallele_11

Handling Dark Ions: Separation of ion chains in the trap

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-15000 -10000 -5000 0 5000 10000

ele

ctr

ic p

ote

ntial /

V

axial direction / mu

axial trap potential

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-15000 -10000 -5000 0 5000 10000

ele

ctr

ic p

ote

ntial /

V

axial direction / mu

axial trap potential

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-15000 -10000 -5000 0 5000 10000

ele

ctr

ic p

ote

ntial /

V

axial direction / mu

axial trap potential

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-15000 -10000 -5000 0 5000 10000

ele

ctr

ic p

ote

ntial /

V

axial direction / mu

axial trap potential

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-15000 -10000 -5000 0 5000 10000

ele

ctr

ic p

ote

ntial /

V

axial direction / mu

axial trap potential

Axial position [µm]

Axi

al t

rap

pin

g p

ote

nti

al[V

]

Page 29: Ldb Convergenze Parallele_11

Handling Dark Ions: Feedback position control

desired position

real position

Voltage control Trap

CCD Image & Real time position determination

Page 30: Ldb Convergenze Parallele_11

Handling Dark Ions: Separation of ion chains in the trap

Vo

ltag

e /

V

Time / s

J. Eble, S. Ulm, P. Zahariev, F. Schmidt-Kaler, KS,

Journal of the Optical Society of America B 27, A99 (2010).

After separation any motional excitation of the dark ion has to be minimized !

Page 31: Ldb Convergenze Parallele_11

Moving ions

• out of the trap for ion implantation connecting solid state quantum systems

• within the trap for quantum information processing

• with heat for the realization of a heat engine

• to investigate the Kibble-Zurek mechanism

Cold

Hot

Work

Page 32: Ldb Convergenze Parallele_11

Scalable Quantum Information with Segmented Ion Traps

J. P. Home, D. Hanneke, J. D. Jost, J. M. Amini, D. Leibfried,

and D. J. Wineland,

“Complete Methods Set for Scalable Ion Trap Quantum

Information Processing”,

Science 325, 1227 (2009).

D. Kielpinski, C. Monroe and D. J. Wineland,

“Architecture for a large-scale ion-trap

quantum computer”

Nature 417, 709 (2002).

Page 33: Ldb Convergenze Parallele_11

Ion Transport in Segmented Traps electrode 1 (size 10 screens) …………………………………………………………..……………………………………..…electrode 2

Size of wavefunction:

a single pixel on a HD screen (2000x1000)

Page 34: Ldb Convergenze Parallele_11

Fast Diabatic Transport in Segmented Microtrap

• A. Walther, F. Ziesel, M. Hettrich , S. Dawkins,

KS, F. Schmidt-Kaler,U.G. Poschinger, PRL 109, 080501 (2012).

• Ryan Bowler, J. Gaebler, Y. Lin, T. R. Tan, D. Hanneke, J. D. Jost, J. P.

Home, D. Leibfried, and D. J. Wineland,

PRL 109, 080502 (2012)

• Blakestad et al., PRL 102, 153002 (2009)

Page 35: Ldb Convergenze Parallele_11

Fast Diabatic Transport in Segmented Microtrap

• fs-laser cut Alumina

• 3-layered sandwich design

• evaporated gold as electrode material

• 31 individual DC segments

• typical trap frequencies:

1.4 MHz (ax.)/3 MHz (rad.)

• possible total transport distance: ~ 5mm

Page 36: Ldb Convergenze Parallele_11

Fast Diabatic Transport in Segmented Microtrap

Page 37: Ldb Convergenze Parallele_11

FPGA

DAC 1

Output → filters → trap segments

Prerequisites: Precision arbitrary waveform source for ion transport

• Virtex 5FXT FPGA

• 64 Mbyte DDR RAM

• 400 MHz Power PC CPU

• 10ns timing

• GB Ethernet

• 64 IO

Page 38: Ldb Convergenze Parallele_11

Prerequisites: Precision arbitrary waveform source for ion transport

• serial 16 bit DACs (TI DAC8814)

• 2.5 MSamples/s/electrode

• Resolution: 0.3 mV

• 12 channels per analog card

• expandable to 4 analog cards Optimized signal routing, to minimize digital cross talk.

Page 39: Ldb Convergenze Parallele_11

P1/2

S1/2

t = 7 ns

397 nm

Doppler cooling D5/2

t = 1 s

729 nm

Sideband cooling

Energ

y

Level scheme of Calcium+

Page 40: Ldb Convergenze Parallele_11

2 Level Atom Harmonic trap

„Dressed“ System

„molecular

Franck Condon“

Picture

„Dressed“ System

Sn ,1

Dn ,1Dn,

Dn ,1

Sn ,1Sn,

„Energy

Ladder“

Picture

S

D

D

S

Laser Excitation of a single Ion

Page 41: Ldb Convergenze Parallele_11

Signature: no further excitation allowed

„Dark state“ |0>

forbidden!

g,0

e,0e,1

g,2

g,1Optical Pumping into the Ground state

e,2

Sideband cooling into the Motional Ground State

Page 42: Ldb Convergenze Parallele_11

P1/2

S1/2

t = 7 ns

397 nm

Doppler cooling D5/2

t = 1 s

729 nm

Sideband cooling

Energ

ie

Level-Scheme of Calcium+

+1/2

-1/2 ~1

0 M

Hz

@ 6

G

~1

0-1

00

GH

z

Raman transition

Qubit-Manipulation

Spin dependent forces Shelving

bright

dark

U. G. Poschinger, et. al, KS, F. Schmidt-Kaler, Journal of Physics B 42,

154013 (2009).

Page 43: Ldb Convergenze Parallele_11

Different Diabatic transport schemes Symmetric transport (back and forth) Asymmetric transport with kick

dis

tan

ce

time

dis

tan

ce

time

Seg 1

Seg 2

Only one

Laser interaction zone

280µm

Page 44: Ldb Convergenze Parallele_11

Different Diabatic transport schemes Symmetric transport (back and forth) Asymmetric transport with kick

dis

tan

ce

time

dis

tan

ce

time

Seg 1

Seg 2

Page 45: Ldb Convergenze Parallele_11

Symmetric Transport electrode 1 (size 10 screens) …………………………………………………………..……………………………………..…electrode 2

Size of wavefunction:

a single pixel on a HD Screen (2000x1000)

Transport Backtransport

Page 46: Ldb Convergenze Parallele_11

Energy measurement

Page 47: Ldb Convergenze Parallele_11

Efficient Energy Measurement

Page 48: Ldb Convergenze Parallele_11

Results of symmetric transport

Pseudo energy

Phonon fit to Rabi oscillations

• Trap periodicity

visible

• Coherent control of

oscillation amplitude

over 4 orders of

magnitude

• < 0.1 phonons

minimal energy

transfer

Dwell time is scanned:

Transport details (each direction):

• 20 sample points

• 8 µs → ~ 11 motion cycles

• 220 µm → to next segment, ~23000

times the size of ion wavepacket

• Speed: >2000 wavepackets/cycle

• ~100 km/h

Note: 𝜂2𝑛 ≪ 1,

well within Lamb-Dicke

regime

→ allows gates after

transport

𝑓𝑡𝑟𝑎𝑝 = 1.4 𝑀𝐻𝑧

Page 49: Ldb Convergenze Parallele_11

Assymmetric Transport electrode 1 (size 10 screens) …………………………………………………………..……………………………………..…electrode 2

Size of wavefunction:

a single pixel on a HD Screen (2000x1000)

Page 50: Ldb Convergenze Parallele_11

Transport with decelleration kick

3.85 V

-3.68 V

• Control via kick voltage or wait time

• demonstration of fast, controlled one-way

transport

• 0.2 phonons minimal energy transfer

Page 51: Ldb Convergenze Parallele_11

Controlled Displacement Kicks

Kick

Coherent state in Fock basis:

P(n) P(n)

Theory Experiment

Page 52: Ldb Convergenze Parallele_11

Controlled Displacement Kicks

Kick

Displaced Fock state in Fock basis:

P(n) P(n)

Theory Experiment

Page 53: Ldb Convergenze Parallele_11

Transport of Spin Motion Entanglement

Transport

p/2 bsb p/2 bsb p bsb

• Very sensitive measurement of trap frequency variations during transport

• No effect of magnetic field gradients due to compensation with Ramsey spectroscopy on

carrier transition

(A. Walther, U. Poschinger, F. Ziesel, M. Hettrich, A. Wiens, J. Welzel, and F. Schmidt-Kaler,

Phys. Rev. A 83, 062329 (2011).

Page 54: Ldb Convergenze Parallele_11

s=390 Hz

Carrier Ramsey Ramsey on blue sideband

Transport of a motional superposition state

without transport

with transport

A. Walther, F. Ziesel, M. Hettrich , S. Dawkins, KS, F. Schmidt-Kaler, U.G. Poschinger, Physical Review Letters 109, 080501 (2012).

Page 55: Ldb Convergenze Parallele_11

Moving Ions

• out of the trap for ion implantation connecting solid state quantum systems

• within the trap for quantum information processing

• with heat for the realization of a heat engine

• to investigate the Kibble-Zurek mechanism

Cold

Hot

Work

Page 56: Ldb Convergenze Parallele_11

Macroscopic Heat engine Converts thermal energy into mechanical work / motion

essential for industry

Carnot efficiency (Sadi Carnot 1823):

𝜂 =Work produced

Heat absorbed=

𝑊

𝑄𝐻≤ 1 −

𝑇𝐶

𝑇𝐻= 1 −

𝛽𝐻

𝛽𝐶

heat heat Heat

Engine

mechanical

work

cold hot

James Watt 1783: 𝜂 ≅ 5 − 7%

Modern power plats: 𝜂 ≅ 30%

maximum

possible value

Page 57: Ldb Convergenze Parallele_11

Downscaling of Heat Engines

Size

Car Engine

mini heat engine

m mm µm nm

Steeneken et al., Nature Phys. 7, 354 (2011)

Blickle et al., Nature Phys 8, 143 (2012)

piezoresistive heat engine

colloidal heat engine

single particle

thermodynamics

? single trapped ion

in a Paul Trap

Quantum regime excessible

Fundamental limit

Page 58: Ldb Convergenze Parallele_11

Single Ion heat engine

Proposal: • Heat engine with one single ion trapped in a Paul trap as working

substance.

– Excellent preparation and control

– Allow for reservoir engineering • detuned lasers Doppler interaction

• electronic noise

• …

• Potential to reach quantum regime

– Quantum heat engines: studied theoretically for >50 years

– No one has been realized yet

Scovil,Schulz-Dubois, PRL (1959)

Hot bath Cold bath

Abah, Rossnagel, Jacob, Deffner, Lutz, Schmidt-Kaler, Singer, Phys. Rev. Lett. 109, 203006 (2012)

Page 59: Ldb Convergenze Parallele_11

Realization: Idea • Converting thermal energy into motion

– Thermal state of ion expands when heated

– Driving the engine in the radial states of motion (linear paul trap) – Converting thermal ernergy of the radial mode into

motion – Storing motional energy in axial mode

heating

Page 60: Ldb Convergenze Parallele_11

Realization: tapered Paul trap angle between rf-rods

𝜔𝑥,𝑦 𝜔𝑥,𝑦(𝑧)

Pseudo potential:

𝑉𝑝 𝑟, 𝑧 =𝑚

2

(𝜔0𝑥2 𝑥2+𝜔0𝑦

2 𝑦2)𝑟04

(𝑟0 + 𝑧 tan𝛼)4+

𝑚

2𝜔0𝑧

2 𝑧2

Coupling between axial and radial modes

𝐻 = ħ𝜔0𝑖 𝑎𝑖†𝑎𝑖 +

1

2− 𝐶 ∙ 𝑧 (𝜔0𝑥

2 𝑥 2 + 𝜔0𝑦2 𝑦 2) 𝐶 =

2𝑚 tan𝜃

𝑟0 𝑖∈ 𝑥,𝑦,𝑧

Difference to

linear Paul trap

Page 61: Ldb Convergenze Parallele_11

The trapped ion as engine gas Doppler heating/cooling in radial direction induces axial displacement

To reach reach large axial amplitudes of movement

• strong radial confinement

• weak axial confinement

Pseudopotential

heating

r z

F

Equilibrium position shifted

Page 62: Ldb Convergenze Parallele_11

A

B C

D

Working cycle

heating

moving

cooling

moving

Driving resonantly

with axial trap freq.

Page 63: Ldb Convergenze Parallele_11

Equivalence to macroscopic Heat Engine

heating

moving

cooling

moving

ignition

expansion

compression

themalizing

Page 64: Ldb Convergenze Parallele_11

Equivalence to macroscopic Heat Engine

Converting thermal energy into motion

=

Heat engine

Classical thermodynamics:

Large ensemble of particles

Page 65: Ldb Convergenze Parallele_11

Quantum Otto Cycle: principle

Isentropic expansion

Isentropic compression

Hot

isochore Cold

isochore

𝑊3

𝑄4

𝑊1

𝑄2

D (ω1,β2)

A (ω1,β1) B (ω2,β1)

C (ω2,β2)

1

2

3

4

β = 1/kT

Page 66: Ldb Convergenze Parallele_11

Quantum Otto Cycle: theory

non-thermal

non-thermal

unitary

unitary

Page 67: Ldb Convergenze Parallele_11

Quantum Otto cycle: efficiency Exact quantum expression:

Adiabaticity Parameter Qi* (Husimi 1953)

– Depends on driving

Adiabatic process: 𝑄∗

1,2 = 1 approximates our process

Sudden switch (extreme): 𝑄∗1,2 = (𝜔1

2 + 𝜔22)/(2𝜔1𝜔2)

Page 68: Ldb Convergenze Parallele_11

Monte Carlo Simulation simulating thermal state of a single ion

High temperture limit - classical trajectories:

• Ensemble of classical realizations

• Thermal probability distribution through Monte-Carlo simulation of laser interaction

Realistic trap geometries:

Finite size method to calculate potentials

including micromotion and realistic dynamics

Probability for spontanous scattering

Momenteum Transfer of Photons

R. Casdorff, R. Blatt, Appl. Phys. B 45, 175 (1988)

K. Singer et al., Rev. Mod. Phys. (2010)

Page 69: Ldb Convergenze Parallele_11

Excitation of the heat engine • Resonant driving of heating and cooling cycles

• Sum over large ensembles of realizations

Thermal states in

radial modes

Coherent

excitation of axial

modes

Steady state due to axial damping force (cooling laser)

Page 70: Ldb Convergenze Parallele_11

Radial energy

start heat engine

Doppler cooling

Thermal ensemble

time

Equilibrum between

heating and cooling

detuning

Heating and cooling:

20% of axial oscillation

work

Page 71: Ldb Convergenze Parallele_11

Phase-space analysis

radial: 0 𝜋 32𝜋

0 12𝜋 𝜋 axial:

• Ensemble average over one axial period

12𝜋

32𝜋

x

x

p

p

α

Page 72: Ldb Convergenze Parallele_11

Phase-space analysis • transformation from thermal energy into coherent motion

DPG 2012 Johannes Roßnagel - University of Mainz 72

axial: radial:

x x v

v

Page 73: Ldb Convergenze Parallele_11

Efficiency at maximum power • Two essential characteristics of HE:

power output and efficiency at maximum power

Power 𝑃 =Work done per cycle

Duration of cycle= −

𝑊1 + 𝑊3

𝑡cycle

Maximization of P for given heat baths and ω1

maximum condition for ω2

𝜔2 𝜔1 = 𝛽1 𝛽2

Adiabatic process (Q*=1):

• High temperture (classical) limit:

𝜂 = 1 −𝛽2

𝛽1= 1 −

𝑇1

𝑇2

• Low temperture limit (for cold bath):

𝜂 = 1 −𝛽2

𝛽1= 1 −

ħ𝜔1

2 𝑘𝑇2

Curzon-Ahlborn Efficiency (1975)

𝜔2 = 2𝜔1 ħ𝛽2

Quantum Efficiency

Page 74: Ldb Convergenze Parallele_11

Efficiency at maximum power

Classical Carnot limit

adiabatic Curzon-Ahlborn

𝜼𝑪𝑨 = 𝟏 − 𝜷𝟐/𝜷𝟏

O. Abah, J. Roßnagel, G. Jacob et al., Phys. Rev. Lett. 109, 203006 (2012)

effic

iency η

sudden switch

𝛽2 𝛽1 = 𝑇1/𝑇2

Engine can run at maximum power 𝜔2 𝜔1 = 𝛽1 𝛽2

Page 75: Ldb Convergenze Parallele_11

Single ion refrigerator • Reverse the thermodynamic

cycle to convert mechanical work into heat flow

• Carnot efficiency for heat pump:

𝜀𝐶 =1

𝜂𝐶=

𝑇𝑐𝑇ℎ − 𝑇𝑐

heat R

mechanical

work

cold hot

heat

Page 76: Ldb Convergenze Parallele_11

Heat pump: working principle

Page 77: Ldb Convergenze Parallele_11

Heat pump: working principle

heat

transport

Page 78: Ldb Convergenze Parallele_11

Single Ion Refrigerator

• Smallest possible refrigerator

• Driving three ion Egyptian mode

• Middle ion transfers heat between two oscillatory reservoirs

• Coupling to all kind of micro-oscillators possible

Page 79: Ldb Convergenze Parallele_11

Heat Transport

Transport oscillation Transport thermal energy

heat transport of radial modes along the crystal

Steady state

Between two heat baths

Hot

Bath Cold

Bath

Transport single Phonons

# ion

# p

honon

1 n

# ion

# p

honon impurity

1 n

G.D. Lin, L.M. Duan, NJP 13 (2011)

Ivanov, Vitanov, Singer, Schmidt-Kaler, arXiv (2010)

Bermudez, Bruderer, Plenio, arXiv (2013)

Page 80: Ldb Convergenze Parallele_11

Squeezed thermal bath

Cooling to ground state

• Heat baths: increasing

and decresing single

phonons

• kT 1/2 ħω

Driving quantum

states

• Storing energy not in

coherent states but in

non-classical states

• Amplifing cat state,

squeezed ground

state…

Non-classical

thermodynamics

• Driving engine by

non-classical

baths

• Squeezed baths

increases

efficiency

• Spin bath,

magnetic gradient

along the trap axis

O. Abah, E. Lutz, arXiv:1303.6558(2013)

Non-classical heat baths:

Page 81: Ldb Convergenze Parallele_11

Squeezed heat engine

squeezing

Phase space:

Thermal state

effective

distribution

becomes larger…

…Impact on axial

movement stronger

Page 82: Ldb Convergenze Parallele_11

Non-thermal heat baths • Introducing squeezed hot reservoir bath:

• Hot bath heats and squeezes thermal state

• 𝐻∗ = 𝐻 + ∆𝐻 𝑛 ∗ = 𝑛 + ∆𝑛 higher effective temperature

squeezin

g

Page 83: Ldb Convergenze Parallele_11

Non-thermal heat baths

Page 84: Ldb Convergenze Parallele_11

Increasing efficiency • Repeat same calculations as before…

𝜂∗ = 1 −𝛽2

𝛽1 1+2 sinh2 𝑟

Limit for large squeezing (𝑟 ≫ 0):

𝜂∗ = 1 −𝛽2

𝛽12 exp (−2𝑟)

Limit for low squeezing (𝑟 → 0):

𝜂∗ = 1 −𝛽2

𝛽1(1 − 2𝑟2)

increases efficiency exponentially

Carnot-limit

𝛽2 𝛽1 = 0.3

𝛽2 𝛽1 = 0.6

𝛽2 𝛽1 = 0.9

Efficiency above Carnot Limit is possible!

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Experimental realization

Holding and

compensation

electrodes

RF-electrodes

Anti-symmetric

supply on all of the

four rods

Mount and endcaps

Gold coated ceramics

Distance ion – endcaps: 4mm

Distance ion – electrodes: 1.5mm

RF driving: 800Vpp at 60MHz

Axial trap frequency: 35kHz

Radial trap frequency: 6MHz

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Moving Ions

• out of the trap for ion implantation connecting solid state quantum systems

• within the trap for quantum information processing

• with heat for the realization of a heat engine

• to investigate the Kibble-Zurek mechanism

Cold

Hot

Work

Page 87: Ldb Convergenze Parallele_11

Observation of the Kibble Zurek scaling law

for defect formation in ion crystals

Page 88: Ldb Convergenze Parallele_11

1976 (Kibble)

symmetry breaking at a second order

phase transitions such that topological

defects form, this may explain formation of

cosmic strings or domain walls

Thomas Kibble

(Imperial London)

Universal principles of defect formation

T. W. B. Kibble, Journal of Physics A 9, 1387 (1976). T. W. B. Kibble, Physics Reports 67, 183 (1980).

Page 89: Ldb Convergenze Parallele_11

1976 (Kibble)

symmetry breaking at a second order

phase transitions such that topological

defects form, this may explain formation of

cosmic strings or domain walls

Thomas Kibble

(Imperial London)

Universal principles of defect formation

Free energy landscape changes

across the critical point from a single

well to a double well potential

Spontaneous symmetry breaking

Page 90: Ldb Convergenze Parallele_11

Universal principles of defect formation

• System response time, thus information transfer,

diverges when approaching critical point

• At some moment, the system becomes non-

adiabatic and freezes

Freezout

timescale

Linear quench

Diverging slow

response

Relative Temperature:

Relaxation time:

W. H. Zurek, Physics Reports 276, 177 (1996).

Page 91: Ldb Convergenze Parallele_11

1976 (Kibble)

symmetry breaking at a second order

phase transitions such that topological

defects form, this may explain formation of

cosmic strings or domain walls W. Zurek

(los Alamos)

Universal principles of defect formation

1985 (Zurek)

Sudden quench though the critical point leads to

defect formation, experiments in solid state phys.

may test theory of universal scaling

• Experiments with rapid cooling of liquid

crystals observe structures

• Experiments for vortex formation in liquid 3He

• Experiments with vortexes in superconductors

2010 (Morigi, Retzger, Plenio et al)

Proposal for KZ study in trapped ions crystals

W. H. Zurek, Nature 317, 505 (1985).

Page 92: Ldb Convergenze Parallele_11

• Landau Ginzburg theory of phase transition for ion trap situation

• Universal scaling found

• Prediction of for the inhomogenious case

Proposal for KZ physics with ion crystals

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Defect formation in ion crystals

Linear

Zig-zag

Zag-zig

Defect

Defect

Double defect

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Experimental setup and parameters

Trap with 11 segments

Controlled by FPGA and

arbitray waveform gen.

/2p = 1.4MHz (rad.)

/2p = 160 – 250kHz (ax.)

Laser cooling /

CCD observation

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Smooth axial compression over critical point

• Exponential soft start and stop

• Low excitation of axial breathing mode

• Slope at critical point variable for variable quench times

• Acurate frequency determination

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Molecular dynamics simulations

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Molecular dynamics simulations Simulation of

ion trajectories

Tiny axial

excitation

No position flips

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Experimental test of the =8/3 power law scaling

= 2.68 ± 0.06 for anisotropy at

critical point of 1.03

= 2.62 ± 0.15 for anisotropy at

critical point of 1.05

fits prediction for the

inhomogenious Kibble Zurek case

with 8/3 = 2.67

Saturation of

defect density

Offset kink

formation

S. Ulm, et. al., KS, accepted at Nat. Com. (2013) 1302.5343. also Pyka et al., arXiv:1211.7005

Page 99: Ldb Convergenze Parallele_11

Summary/Outlook Paul-trap successfully established as first

deterministic source of single ions Verification of nm resolution and generation of NV

Scalable diabatic transport of a ground state

cooled ion Splitting of Ion chains with combined gate

operations Numerical simulation and prototype Using squeezed states to increase efficiency Realization of the Kibble-Zurek mechanism Tranisition between inhomogeneous and

homogeneous KZM by shaping the potentials

Cold

Hot

Work

Page 100: Ldb Convergenze Parallele_11

www.quantenbit.de

Ion Light Interface

(FSK) Rydberg Ions (FSK) Zig-Zag Ion Crystals

(KS/FSK) Quantum Sim (RG)

Ion Implantation (KS)

QI with Ions (UGP/FSK)

www.quantenbit.de

PhD,

Postdoc

positions!

A. Bautista, S. Dawkins, C. Degüther, T. Feldker, R. Gerritsma,

M. Hettrich, G. Jacob, H. Kaufmann, A. Kesser, N. Kurz, U.G. Poschinger, J. Roßnagel, T. Ruster, F. Schmidt-Kaler, K. Singer, S. Ulm, A. Walther, C. Warschburger, J. Welzel,

S. Wolf, F. Ziesel

Single Ion Heat Engine (KS)