Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 26: Quantum Dots and Wires: Quantum Optics I

HL 26.3: Vortrag

Dienstag, 8. März 2016, 10:15–10:30, H16

Transfer of a quantum state from a photonic qubit to a gate defined quantum dot — •Benjamin Jöcker¹, Pascal Cerfontaine¹, Beata Kardynal², and Hendrik Bluhm¹ — ¹JARA-Institute for Quantum Information, RWTH Aachen University, D-52056 Aachen, Germany — ²Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, D-52425 Jülich, Germany

An interface between a well-functioning, scalable stationary and a photonic qubit could substantially advance quantum communication applications and serve as an interconnect between future quantum processors. Qubits consisting of gate-defined quantum dots in GaAs are electrically controllable with high fidelity, whereas self-assembled quantum dots are established as an optical interface.
Here, we discuss a procedure to transfer the state of a photonic qubit to a quantum dot spin qubit. In the device under consideration a gate-defined quantum dot is tunnel-coupled to an optically addressable self-assembled quantum dot. When a photon is absorbed in the latter, an exciton is created whose spin configuration depends on the polarization of the photon. By applying an in-plane magnetic field, one can optically address exciton states with identical hole spin. As a result, no quantum information remains in the self-assembled quantum dot when the electron is transferred adiabatically to the gate-defined quantum dot. Using experimentally realistic parameters, we find that this transfer can be completed within the coherence time. We also consider an extension of the protocol to two-electron spin qubits, which have the advantage of being controllable via the exchange interaction.