Salient signatures of entanglement in the surrounding environment

TL;DR

This paper proposes a model where entanglement in a quantum system can be detected through indirect, coarse measurements of its environment, revealing signatures of entanglement via observable environmental effects.

Contribution

It introduces a novel approach linking entanglement witnesses to environmental signatures, enabling indirect detection of entanglement through macroscopic observations.

Findings

Gas cloud accelerates based on entanglement witness sign

Dielectric polarization depends on entanglement presence

Electromagnetic quadratures are displaced by entanglement signatures

Abstract

We develop a model in which presence of entanglement in a quantum system can be confirmed through coarse observations of the environment surrounding the system. This counter-intuitive effect becomes possible when interaction between the system and its environment is proportional to an observable being an entanglement witness. While presenting intuitive examples we show that: i) a cloud of an ideal gas, when subject to a linear potential coupled with the entanglement witness, accelerates in the direction dictated by the sign of the witness; ii) when the environment is a radiation field, the direction of dielectric polarization depends on the presence of entanglement; iii) quadratures of electromagnetic field in a cavity coupled with two qubits (or a four-level atom) are displaced in the same manner.