Experimental investigation of initial system-environment correlations via trace distance evolution

TL;DR

This paper provides the first experimental evidence that initial system-environment correlations can increase the distinguishability of quantum states, using an all-optical setup with entangled photons and controlled correlations.

Contribution

It introduces an experimental method to observe how initial correlations affect trace distance evolution in open quantum systems.

Findings

Experimental confirmation of trace distance increase due to initial correlations

Use of optical setup with entangled photons and spatial light modulator

Demonstration of controlled system-environment correlations

Abstract

The trace distance between two states of an open quantum system quantifies their distinguishability, and for a fixed environmental state can increase above its initial value only in the presence of initial system-environment correlations. We provide for the first time experimental evidence of such a behavior. In our all-optical apparatus we exploit spontaneous parametric down conversion as a source of polarization entangled states, and a spatial light modulator to introduce in a general fashion correlations between the polarization and the momentum degrees of freedom, which act as environment.