# Sensing single atoms in a cavity using a broadband squeezed light

## TL;DR

This paper explores how broadband squeezed light can be used to detect a single atom in a cavity by observing changes in photon number states and squeezing properties, advancing quantum sensing techniques.

## Contribution

It introduces a novel method for sensing single atoms in a cavity using broadband squeezed light, highlighting the transfer of photon states and changes in squeezing.

## Key findings

- Detection of single atoms via photon state transfer
- Observation of squeezing loss indicating atom presence
- Analysis of quantum fluctuations and multiphoton transitions

## Abstract

We investigate a single atom cavity-QED system directly driven by a broadband squeezed light. We demonstrate how the squeezed radiation can be used to sense the presence of a single atom in a cavity. This happens by transferring one of the photons from the field in a state with even number of photons to the atom and thereby populating odd number Fock states. Specifically, the presence of the atom is sensed by remarkable changing in the presence of one photon and the loss of squeezing of the cavity field. A complete study of quantum fluctuations and the excitation of multiphoton transitions is given.