# A Quantum Spectrometer for Arbitrary Noise

## TL;DR

This paper introduces a quantum spectrometer technique capable of recovering the spectrum of non-Markovian noise in harmonic oscillators, with applications in quantum sensing and metrology.

## Contribution

The authors develop a minimal-conditions quantum spectrometer method for non-Markovian noise spectrum recovery, demonstrated in a nanosphere levitated in a Paul trap scenario.

## Key findings

- Effective probing of electric field noise from 10^2 to 10^6 Hz
- Resolution inversely proportional to measurement time
- Applicable in quantum sensing and foundational experiments

## Abstract

We present a technique for recovering the spectrum of a non-Markovian bosonic bath and/or non-Markovian noises coupled to an harmonic oscillator. The treatment is valid under the conditions that the environment is large and hot compared to the oscillator, and that its temporal auto-correlation functions are symmetric with respect to time translation and reflection -- criteria which we consider fairly minimal. We model a demonstration of the technique as deployed in the experimental scenario of a nanosphere levitated in a Paul trap, and show that it would effectively probe the spectrum of an electric field noise source from $10^2\,-\,10^6$ Hz with a resolution inversely proportional to the measurement time. This technique may be deployed in quantum sensing, metrology, computing, and in experimental probes of foundational questions