Single-shot optical readout of a quantum bit using cavity quantum electrodynamics

TL;DR

This paper introduces a cavity QED-based method for single-shot optical readout of a qubit, capable of high-fidelity detection without the need for cycling transitions, applicable to quantum dots and similar systems.

Contribution

The authors propose a novel cavity QED technique for qubit readout that improves fidelity and applicability over traditional fluorescence methods.

Findings

Readout fidelity exceeds 0.99 under various conditions

Method works without cycling transitions

Applicable to quantum dot spins and similar qubits

Abstract

We propose a method to perform single-shot optical readout of a quantum bit (qubit) using cavity quantum electrodynamics. We selectively couple the optical transitions associated with different qubit basis states to the cavity, and utilize the change in cavity transmissivity to generate a qubit readout signal composed of many photons. We show that this approach enables single-shot optical readout even when the qubit does not have a good cycling transition required for standard resonance fluorescence measurements. We calculate the probability that the measurement detects the correct spin state using the example of a quantum dot spin under various experimental conditions and demonstrate that it can exceed 0.99.