Scalable photonic quantum computing assisted by quantum-dot spin in double-sided optical microcavity

TL;DR

This paper proposes a scalable approach to photonic quantum computing using quantum-dot spins in double-sided microcavities, enabling high-fidelity multi-qubit gates in both strong and weak coupling regimes.

Contribution

It introduces a deterministic controlled-not gate and a quantum circuit for a three-photon Toffoli gate leveraging cavity QED effects with potential for scalable quantum computing.

Findings

High fidelities achievable with low cavity leakage

Devices operate effectively in both strong and weak coupling regimes

Potential for multi-qubit photonic quantum gates

Abstract

We investigate the possibility to achieve scalable photonic quantum computing by the giant optical circular birefringence induced by a quantum-dot spin in a double-sided optical microcavity as a result of cavity quantum electrodynamics. We construct a deterministic controlled-not gate on two photonic qubits by two single-photon input-output processes and the readout on an electron-medium spin confined in an optical resonant microcavity. This idea could be applied to multi-qubit gates on photonic qubits and we give the quantum circuit for a three-photon Toffoli gate. High fidelities and high efficiencies could be achieved when the side leakage to the cavity loss rate is low. It is worth pointing out that our devices work in both the strong and the weak coupling regimes.