Enhancing low-temperature quantum thermometry via sequential measurements

TL;DR

This paper introduces a sequential measurement protocol that significantly improves low-temperature quantum thermometry precision by leveraging correlated outputs, achieving Heisenberg scaling and high spectral resolution.

Contribution

The paper presents a novel sequential measurement scheme that enhances low-temperature quantum thermometry beyond independent measurements, with a focus on correlated outputs and spectral resolution.

Findings

Achieves Heisenberg scaling in signal-to-noise ratio for small N

Correlated outputs determine the final precision, scaling as N^2

Enables high-resolution quantum spectroscopy of thermal noise

Abstract

We propose a sequential measurement protocol for accurate low-temperature estimation. The resulting correlated outputs significantly enhance the low temperature precision compared to that of the independent measurement scheme. This enhancement manifests a Heisenberg scaling of the signal-to-noise ratio for small measurement numbers $N$. Detailed analysis reveals that the final precision is determined by the pair correlation of the sequential outputs, which produces a dependence $N^2$ on the signal-to-noise ratio. Remarkably, we find that quantum thermometry within the sequential protocol functions as a high-resolution quantum spectroscopy of the thermal noise, underscoring the pivotal role of the sequential measurements in enhancing the spectral resolution and the temperature estimation precision. Our methodology incorporates sequential measurement into low-temperature quantum thermometry, representing an important advancement in low-temperature measurement.