Photon-resolved Floquet theory approach to spectroscopic quantum sensing

TL;DR

This paper introduces Photon-resolved Floquet theory (PRFT), a new framework for predicting measurement fluctuations in quantum sensing, enabling significant improvements in sensitivity by analyzing higher order photon statistics.

Contribution

The paper develops PRFT to accurately predict measurement statistics and fluctuations in spectroscopic quantum sensing, surpassing semiclassical methods and enhancing sensor sensitivity.

Findings

PRFT predicts higher order photon measurement statistics.

Application to Rydberg atoms shows improved sensing sensitivity.

PRFT can enhance quantum sensor performance by orders of magnitude.

Abstract

Spectroscopic methods play a vital role in quantum sensing, which uses the quantized nature of atoms or molecules to reach astonishing precision for sensing of, e.g., electric or magnetic fields. In the theoretical treatment, one typically invokes semiclassical methods to describe the light-matter interaction between quantum emitters, e.g., atoms or molecules, and a strong coherent laser field. However, these semiclassical approaches struggle to predict the stochastic measurement fluctuations beyond the mean value, necessary to predict the sensitivity of spectroscopic quantum sensing protocols. Here, we develop a theoretical framework based on the recently developed Photon-resolved Floquet theory (PRFT) which is capable to predict the measurement statistics describing higher order statistics of coherent quantum states of light. The PRFT constructs flow equations for the cumulants of the photonic measurement statistics utilizing only the semiclassical dynamics of the matter system. We apply the PRFT to spectroscopic quantum sensing using dissipative two-level and four-level systems (describing electric field sensing with Rydberg atoms), and demonstrate how to calculate the Fisher information of the measurement statistics with respect to various system parameters. In doing so, we demonstrate that the PRFT is a flexible tool allowing to improve the sensitivity of spectroscopic quantum sensing devices by several orders of magnitudes.