Nonequilibrium readiness and precision of Gaussian quantum thermometers

Luca Mancino,Marco G Genoni,Mauro Paternostro,Marco Barbieri

doi:10.1103/physrevresearch.2.033498

Abstract

The dimensionality of a thermometer is key in the design of quantum thermometry schemes. In general, the phenomenology that is typical of finite-dimensional quantum thermometry does not apply to infinite dimensional ones. We analyse the dynamical and metrological features of non-equilibrium Gaussian Quantum Thermometers: on one hand, we highlight how quantum entanglement can enhance the readiness of composite Gaussian thermometers; on the other hand, we show that non-equilibrium conditions do not guarantee the best sensitivities in temperature estimation, thus suggesting the reassessment of the working principles of quantum thermometry.

Highlights

The direct assessment of the properties of quantum mechanical systems is not always possible or convenient: In general, any direct interference would alter the properties of the system, possibly spoiling them
We analyze the dynamical and metrological features of nonequilibrium Gaussian quantum thermometers: On one hand, we highlight how quantum entanglement can enhance the readiness of composite Gaussian thermometers; on the other hand, we show that nonequilibrium conditions do not guarantee the best sensitivities in temperature estimation, suggesting the reassessment of some of the working principles underpinning quantum thermometry
While the formalism used to illustrate our findings is that of Gaussian quantum states and operations [34,35,36], our study addresses a wealth of physical situations of strong experimental relevance for quantum probing, from micro-/nanomechanical oscillators driven by optical or electric forces to microwave fields in superconducting waveguides and atomic spin systems collectively coupled to driving fields [37]

Summary

INTRODUCTION

The direct assessment of the properties of quantum mechanical systems is not always possible or convenient: In general, any direct interference would alter the properties of the system, possibly spoiling them. Most of the current investigations in quantum thermometry use two-level systems as thermometers [8,9,10,11], shedding light on the link between the equilibrium heat capacity of such microscopic probes and the amount of information that can be gathered on the temperature of the environment [12,13,14], introducing bounds on the irreversible entropy production of the probe [15,16,17], and clarifying the extent of the advantages resulting from finite-time interactions for both temperature discrimination and estimation [14,18].

PHYSICAL MODEL

GEOMETRIC CONSIDERATIONS

METROLOGICAL CONSIDERATIONS

CONCLUSION