# Randomisation of Pulse Phases for Unambiguous and Robust Quantum Sensing

## TL;DR

This paper introduces a universal quantum sensing method that employs randomised pulse phases to improve signal clarity and robustness, effectively reducing errors from pulse imperfections and finite pulse widths.

## Contribution

The authors develop and experimentally validate a novel randomisation technique for dynamical decoupling in quantum sensing, enhancing accuracy and unambiguity over traditional methods.

## Key findings

- Improved signal fidelity in nanoscale nuclear spin sensing.
- Enhanced robustness in AC magnetometry.
- Effective suppression of pulse-induced errors.

## Abstract

We develop theoretically and demonstrate experimentally a universal dynamical decoupling method for robust quantum sensing with unambiguous signal identification. Our method uses randomisation of control pulses to suppress simultaneously two types of errors in the measured spectra that would otherwise lead to false signal identification. These are spurious responses due to finite-width $\pi$ pulses, as well as signal distortion caused by $\pi$ pulse imperfections. For the cases of nanoscale nuclear spin sensing and AC magnetometry, we benchmark the performance of the protocol with a single nitrogen vacancy centre in diamond against widely used non-randomised pulse sequences. Our method is general and can be combined with existing multipulse quantum sensing sequences to enhance their performance.