Scalable quantum computing based on stationary spin qubits in coupled quantum dots inside double-sided optical microcavities

TL;DR

This paper proposes a scalable quantum computing architecture using stationary electron-spin qubits in coupled quantum dots within double-sided optical microcavities, enabling universal quantum gates with high fidelity and efficiency.

Contribution

It introduces a novel, compact, and scalable design for quantum gates based on cavity quantum electrodynamics with solid-state spin qubits, requiring no additional qubits.

Findings

Design of universal quantum gates including CNOT and Toffoli gates.

High fidelity and efficiency achievable with current technology.

Devices are scalable, compact, and based on stationary solid-state qubits.

Abstract

Quantum logic gates are the key elements in quantum computing. Here we investigate the possibility of achieving a scalable and compact quantum computing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the compact quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including the two-qubit CNOT gate and the three-qubit Toffoli gate. They are compact and economic, and they do not require additional electron-spin qubits. Moreover, our devices have good scalability and are attractive as they both are based on solid-state quantum systems and the qubits are stationary. They are feasible with the current experimental technology, and both high fidelity and high efficiency can be achieved when the ratio of the side leakage to the cavity decay is low.