Initial state preparation with dynamically generated system-environment correlations

TL;DR

This paper explores how initial correlations between a quantum system and its environment influence the system's dynamics, proposing methods to prepare initial states that avoid unphysical behaviors in open quantum systems.

Contribution

It introduces a systematic approach to initial state preparation that accounts for system-environment correlations, improving the realism of open quantum system models.

Findings

Explicit methods to avoid unphysical initial behaviors

Analytical results for correlated initial states

Guidelines for experimental and theoretical setups

Abstract

The dependence of the dynamics of open quantum systems upon initial correlations between the system and environment is an utterly important yet poorly understood subject. For technical convenience most prior studies assume factorizable initial states where the system and its environments are uncorrelated, but these conditions are not very realistic and give rise to peculiar behaviors. One distinct feature is the rapid build up or a sudden jolt of physical quantities immediately after the system is brought in contact with its environments. The ultimate cause of this is an initial imbalance between system-environment correlations and coupling. In this note we demonstrate explicitly how to avoid these unphysical behaviors by proper adjustments of correlations and/or the coupling, for setups of both theoretical and experimental interest. We provide simple analytical results in terms of quantities that appear in linear (as opposed to affine) master equations derived for factorized initial states.