Determining the squeezing in multimode fields using nonlocal quantum probes

TL;DR

This paper introduces a method using nonlocal quantum probes to determine the squeezing parameter of multimode fields by analyzing the dynamics of two coupled two-level systems interacting with correlated Gaussian states.

Contribution

The study presents a novel dynamical quantum probing scheme that links nonlocal coherence revivals to the squeezing parameter in multimode Gaussian environments.

Findings

Revival of nonlocal coherences indicates squeezing levels.

Perfect revivals occur even with nonentangled correlated modes.

Connection established between coherence revivals and environmental correlation coefficients.

Abstract

We present a scheme allowing to access the squeezing parameter of multimode fields by means of the dynamics of nonlocal quantum probes. The model under consideration is composed of two two-level systems which are coupled locally to an environment consisting of nonlocally correlated field modes given by two-mode Gaussian states. Introducing independently switchable interactions, one observes revivals of nonlocal coherences of the two-qubit system which are unambiguously connected to the squeezing parameter of the Gaussian environmental states. Thus, the locally interacting two two-level systems represent a dynamical quantum probe for the squeezing in multimode fields. It is finally demonstrated that perfectly reviving nonlocal coherences also persists for nonentangled correlated field modes and an explanation for this phenomenon is presented by connecting it to the correlation coefficient of the environmental coupling operators.