Sensitivity of quantum gate fidelity to laser phase and intensity noise

TL;DR

This paper investigates how laser phase and intensity noise affect the fidelity of quantum gates on neutral atom qubits, providing models and guidelines to optimize laser parameters for improved quantum gate performance.

Contribution

It develops analytical and numerical models to quantify laser noise effects on quantum gate fidelity and offers strategies to enhance fidelity by tuning Rabi frequency relative to noise features.

Findings

Gate fidelity is sensitive to laser phase and intensity noise.

Optimal Rabi frequency selection can mitigate noise effects.

Established laser noise level requirements for high-fidelity gates.

Abstract

The fidelity of gate operations on neutral atom qubits is often limited by fluctuations of the laser drive. Here, we quantify the sensitivity of quantum gate fidelities to laser phase and intensity noise. We first develop models to identify features observed in laser self-heterodyne noise spectra, focusing on the effects of white noise and servo bumps. In the weak-noise regime, characteristic of well-stabilized lasers, we show that an analytical theory based on a perturbative solution of a master equation agrees very well with numerical simulations that incorporate phase noise. We compute quantum gate fidelities for one- and two-photon Rabi oscillations and show that they can be enhanced by an appropriate choice of Rabi frequency relative to spectral noise peaks. We also analyze the influence of intensity noise with spectral support smaller than the Rabi frequency. Our results establish requirements on laser noise levels needed to achieve desired gate fidelities.