Using Interaction-Based Readouts to Approach the Ultimate Limit of Detection Noise Robustness for Quantum-Enhanced Metrology in Collective Spin Systems

TL;DR

This paper derives a fundamental sensitivity bound for quantum-enhanced metrology in collective spin systems with detection noise and introduces an interaction-based readout method that approaches this limit, improving robustness against noise.

Contribution

It presents a new interaction-based readout scheme that nearly reaches the fundamental noise robustness bound for various quantum states in collective spin systems.

Findings

The proposed readout significantly outperforms recent methods.

It approaches the fundamental detection noise bound.

Applicable to multiple quantum state generation methods.

Abstract

I consider the role of detection noise in quantum-enhanced metrology in collective spin systems, and derive a fundamental bound for the maximum obtainable sensitivity for a given level of added detection noise. I then present an interaction-based readout utilising the commonly used one-axis twisting scheme that approaches this bound for states generated via several commonly considered methods of generating quantum enhancement, such as one-axis twisting, two-axis counter-twisting, twist-and-turn squeezing, quantum non-demolition measurements, and adiabatically scanning through a quantum phase transition. I demonstrate that this method performs significantly better than other recently proposed interaction-based readouts. These results may help provide improved sensitivity for quantum sensing devices in the presence of unavoidable detection noise.