The role of initial system-environment correlations with a spin environment

TL;DR

This paper investigates the impact of initial system-environment correlations on the dynamics of open quantum systems, demonstrating their significant and non-trivial effects through exact solutions involving a spin environment.

Contribution

It provides an exact solution for a two-level system with initial correlations in a spin environment, highlighting their importance in quantum dynamics.

Findings

Initial correlations significantly affect system dynamics.

Exact solutions reveal non-trivial effects of correlations.

Entanglement dynamics are influenced by initial correlations.

Abstract

Open quantum systems are a subject of immense interest as their understanding is crucial in the implementation of modern quantum technologies. In the study of their dynamics, the role of the initial system-environment correlations is commonly ignored. In this work, to gain insights into the role of these correlations, we solve an exactly solvable model of a single two-level system interacting with a spin environment, with the initial system state prepared by a suitable unitary operation. By solving the dynamics exactly for arbitrary system-environment coupling strength while taking into account the initial system-environment correlations, we show that the effect of the initial correlations is, in general, very significant and non-trivial. To further highlight the importance of the initial system-environment correlations, we also extend our study to investigate the dynamics of the entanglement between two two-level systems interacting with a common spin environment.