Criticality-enhanced quantum sensor at finite temperature

TL;DR

This paper introduces a quantum sensing method leveraging thermodynamic criticality at finite temperature, enabling high-precision measurements without the need for ultralow temperatures, thus broadening practical quantum metrology applications.

Contribution

It proposes a novel quantum sensing scheme using thermodynamic criticality at finite temperature, expanding quantum critical metrology beyond zero-temperature limitations.

Findings

Thermodynamic criticality enhances sensing precision.

Quantum sensing can be effective without ultralow-temperature cooling.

The scheme applies to the Dicke model with phase transition.

Abstract

Conventional criticality-based quantum metrological schemes work only at zero or very low temperature because the quantum uncertainty around the quantum phase-transition point is generally erased by thermal fluctuations with the increase of temperature. Such an ultralow-temperature requirement severely restricts the development of quantum critical metrology. In this paper, we propose a thermodynamic-criticality-enhanced quantum sensing scenario at finite temperature. In our scheme, a qubit is employed as a quantum sensor to estimate parameters of interest in the Dicke model which experiences a thermodynamic phase transition. It is revealed that the thermodynamic criticality of the Dicke model can significantly improve the sensing precision. Enriching the scope of quantum critical metrology, our finding provides a possibility to realize highly sensitive quantum sensing without cooling.