Quantum sensing with a single-qubit pseudo-Hermitian system

TL;DR

This paper proposes a novel single-qubit pseudo-Hermitian quantum sensor that leverages divergent susceptibility for enhanced measurement sensitivity, potentially outperforming traditional sensors in noisy environments.

Contribution

It introduces a method to realize a pseudo-Hermitian sensor from a two-qubit Hermitian system, expanding the application of non-Hermitian physics in quantum sensing.

Findings

Pseudo-Hermitian sensor exhibits divergent susceptibility without exceptional points.

The approach can be implemented with current qubit technology.

Potential to improve noise resilience in quantum measurements.

Abstract

Quantum sensing exploits fundamental features of quantum system to achieve highly efficient measurement of physical quantities. Here, we propose a strategy to realize a single-qubit pseudo-Hermitian sensor from a dilated two-qubit Hermitian system. The pseudo-Hermitian sensor exhibits divergent susceptibility in dynamical evolution that does not necessarily involve exceptional point. We demonstrate its potential advantages to overcome noises that cannot be averaged out by repetitive measurements. The proposal is feasible with the state-of-art experimental capability in a variety of qubit systems, and represents a step towards the application of non-Hermitian physics in quantum sensing.