Quantum metrology and estimation of Unruh effect

TL;DR

This paper investigates quantum metrology techniques for estimating the Unruh effect using entangled detectors, highlighting how local interactions and parameter adjustments can enhance measurement precision without requiring high accelerations.

Contribution

It introduces a model with local interactions that improves estimation precision by optimizing coupling strength, interaction time, and energy gap, avoiding cavity use.

Findings

Quantum Fisher information is affected by probe state and interaction.

Precision improves with increased coupling strength and interaction time.

High acceleration is not necessary for effective quantum metrology.

Abstract

We study the quantum metrology for a pair of entangled Unruh-Dewitt detectors when one of them is accelerated and coupled to a massless scalar field. Comparing with previous schemes, our model requires only local interaction and avoids the use of cavities in the probe state preparation process. We show that the probe state preparation and the interaction between the accelerated detector and the external field have significant effects on the value of quantum Fisher information, correspondingly pose variable ultimate limit of precision in the estimation of Unruh effect. We find that the precision of the estimation can be improved by a larger effective coupling strength and a longer interaction time. Alternatively, the energy gap of the detector has a range that can provide us a better precision. Thus we may adjust those parameters and attain a higher precision in the estimation. We also find that an extremely high acceleration is not required in the quantum metrology process.