Optically-controlled logic gates for two spin qubits in vertically-coupled quantum dots

TL;DR

This paper proposes an optically-controlled interaction mechanism between electron spins in vertically-stacked double quantum dots, enabling fast two-qubit gates with minimal effects from decoherence and spontaneous emission.

Contribution

It introduces a novel exciton-mediated interaction for spin qubits in quantum dots, allowing rapid two-qubit gate operations with robustness against certain decoherence effects.

Findings

Fast two-qubit gates achievable within exciton relaxation times

Negative effects of hole-mixing and spontaneous emission are manageable

Interaction mechanism suitable for quantum computing applications

Abstract

We describe an interaction mechanism between electron spins in a vertically-stacked double quantum dot that can be used for controlled two-qubit operations. This interaction is mediated by excitons confined within, and delocalized over, the double dot. We show that gates equivalent to the SQRT-SWAP gate can be obtained in times much less than the exciton relaxation time and that the negative effects of hole-mixing and spontaneous emission do not seriously affect these results.