Non-Markovian temperature sensing

TL;DR

This paper explores how non-Markovian dynamics can enhance the performance of a single-qubit quantum thermometer, revealing ways to optimize sensitivity and improve precision through reservoir engineering.

Contribution

It introduces an exact numerical approach to study non-Markovian effects in quantum thermometry, surpassing traditional approximations and identifying conditions for improved sensing accuracy.

Findings

Non-Markovian effects can boost estimation efficiency.

Optimizing coupling operators enhances sensitivity.

Strong coupling can significantly improve long-time sensing precision.

Abstract

We investigate the sensing performance of a single-qubit quantum thermometer within a non-Markovian dynamical framework. By employing an exactly numerical hierarchical equations of the motion method, we go beyond traditional paradigms of the Born-Markov theory, the pure dephasing mechanism, and the weak-coupling approximation, which were commonly used in many previous studies of quantum thermometry. We find (i) the non-Markovian characteristics may boost the estimation efficiency, (ii) the sensitivity of quantum thermometry can be effectively optimized by engineering the proportions of different coupling operators in the whole sensor-reservoir interaction Hamiltonian, and (iii) a threshold, above which the strong sensor-reservoir coupling can significantly enhance the sensing precision in the long-encoding-time regime. Our results may have certain applications for high-resolution quantum thermometry.