High-precision estimation of the parameters in the reservoir via the two-level system

TL;DR

This paper introduces a high-precision method for estimating system and environmental parameters using a two-level atom system, highlighting the role of entanglement and superposition states in enhancing measurement accuracy.

Contribution

It presents a novel approach to parameter estimation, including squeezing strength, via quantum Fisher information, and demonstrates improvements using entangled and two-qubit probes.

Findings

Entangled and superposition states improve estimation precision.

Fidelity can be enhanced with two-qubit probes.

Quantum Fisher information exhibits a return phenomenon during estimation.

Abstract

A scheme is proposed to estimate the system and environmental parameter, the detuning, temperature and the squeezing strength with a high precision by the two-level atom system. It hasn't been reported that the squeezing strength estimation through quantum Fisher information. We find entangled state and optimal superposition state are beneficial for parameter estimation with one-qubit probe by calculating quantum Fisher information and fidelity. And the fidelity between initial and final states of the atom can be improved via the two-qubit probe. Moreover, the phenomenon of quantum Fisher information return occurs when the detuning or the temperature is estimated. Our work provides a basis for precision measurement technology and quantum information processing.