# Quantum thermometry in a squeezed thermal bath

## TL;DR

This paper investigates how squeezing in a thermal bath affects quantum thermometry, analyzing dephasing, optimal measurement strategies, and the role of entanglement in improving temperature estimation precision.

## Contribution

It introduces a detailed analysis of quantum Fisher information dynamics in squeezed baths and explores multi-qubit and entangled probe strategies for enhanced thermometry.

## Key findings

- Squeezing can reduce the number of channel uses needed for optimal thermometry.
- Increasing qubit number does not always improve temperature estimation precision.
- Parallel strategies and W states can enhance quantum thermometry performance.

## Abstract

We address the dephasing dynamics of the quantum Fisher information (QFI) for the process of quantum thermometry with probes coupled to squeezed thermal baths via the nondemolition interaction. We also calculate the upper bound for the parameter estimation and investigate how the optimal estimation is affected by the initial conditions and decoherence, particularly the squeezing parameters. Moreover, the feasibility of the optimal measurement of the temperature is discussed in detail. Then, the results are generalized for entangled probes and the multi-qubit scenarios for probing the temperature are analysed. Our results show that the squeezing can decrease the number of channel uses for optimal thermometry. Comparing different schemes for multi-qubit estimation, we find that an increase in the number of the qubits, interacting with the channel, does not necessarily vary the precision of estimating the temperature. Besides, we discuss the enhancement of the quantum thermometry using the parallel strategy and starting from the W state.