Witness for initial correlations among environments

TL;DR

This paper introduces a method to detect initial correlations among environments in a quantum system using trace distance, enabling better control of open quantum system dynamics.

Contribution

It presents a novel witness based on trace distance to identify initial environmental correlations through measurements on the open system.

Findings

Initial environmental correlations affect the growth of trace distance.

A tight upper bound for trace distance growth indicates environmental correlations.

The method allows detection of environmental correlations under specific conditions.

Abstract

A quantum system inevitably interacts with its surroundings. In general, one does not have detailed information on an environment. Identifying the environmental features can help us to control the environment and its effects on the dynamics of an open system. Here, we consider a tripartite system and introduce a witness for the initial correlations among environments by means of the concept of the trace distance. Due to the existence of the initial environmental correlations, a tight upper bound is obtained for the growth of the trace distance of open quantum system states. Therefore, the initial correlations among the environments subject to particular conditions can be detected by measurements on the open system.