# Noise Spectroscopy with a Quantum Gas

## TL;DR

This paper introduces a method to analyze microwave field spectra and correlations using ultra cold quantum gases, enabling local noise characterization of electromagnetic fields with high temporal resolution.

## Contribution

The work presents a novel quantum gas-based technique for local spectral and correlation analysis of microwave fields, validated through experiments on an atom chip.

## Key findings

- Successful reconstruction of microwave field spectra and correlations.
- Verification of theoretical models with experimental data.
- Potential application in quantum electronic circuit noise analysis.

## Abstract

We report on the spectral analysis and the local measurement of intensity correlations of microwave fields using ultra cold quantum gases. The fluctuations of the electromagnetic field induce spin flips in a magnetically trapped quantum gas and generate a multi-mode atomlaser. The output of the atomlaser is measured with high temporal resolution on the single atom level, from which the spectrum and intensity correlations of the generating microwave field are reconstructed. We give a theoretical description of the atomlaser output and its correlations in response to resonant microwave fields and verify the model with measurements on an atom chip. The measurement technique is applicable for the local analysis of classical and quantum noise of electromagnetic fields, for example on chips, in the vicinity of quantum electronic circuits.