Asymmetric quantum dots are coupled through

an applied electric field

E. A. Stinaff et al, Science 311, 636 (2006).

Why CQDs?

Coupling With Applied Field

Fabrication

Coupling Mechanism

Scaling Up

1 Scalable qubits Each dot represents a qubit

2 Long-lived Spin of unpaired electron or hole

3 Ultra-fast Optically excited states as auxiliary levels

(laser pulses)

1 2 3

Asymmetric pair of InAs Quantum Dots

Exciton Notation:

Indirect

Resonance

Direct

Coupling = Resonance = Anticrossing Condition: Optical Excitation,

Tunneling, Indirect Transitions Possible

Bottom Layer InAs QDs

GaAs Tunneling Barrier

Top Layer InAs QDs

Asymmetric QDs by Design

Distinct Optical Transitions

Distinguishing Individual QDs

…Scalability

Model Without

Tunneling & Spin

1 2 3Model WithTunneling &

Spin

Experimental

SpectrumResonance At