Quantum Simulation of single-qubit thermometry using linear optics

TL;DR

This paper demonstrates a linear-optical simulation of a single-qubit thermometry process, exploring how coherence and non-equilibrium states influence temperature measurement accuracy.

Contribution

It introduces a novel linear-optical simulation method for single-qubit thermometry, analyzing the impact of coherence and non-equilibrium states on thermometric performance.

Findings

Coherence affects the thermometry accuracy.

Non-equilibrium states can enhance measurement sensitivity.

Thermalisation propensity is linked to Helmholtz free energy.

Abstract

Standard thermometry employs the thermalisation of a probe with the system of interest. This approach can be extended by incorporating the possibility of using the non-equilibrium states of the probe, and the presence of coherence. Here, we illustrate how these concepts apply to the single-qubit thermometer introduced by Jevtic et al. by performing a simulation of the qubit-environment interaction in a linear-optical device. We discuss the role of the coherence, and how this affects the usefulness of non-equilibrium conditions. The origin of the observed behaviour is traced back to the propensity to thermalisation, as captured by the Helmholtz free energy.