Lazy states: sufficient and necessary condition for zero quantum entropy rates under any coupling to the environment

TL;DR

This paper characterizes lazy states, a class of system-environment states with zero entropy rate under any interaction, enabling detection of quantum correlations and estimation of dissipation in open quantum systems.

Contribution

It introduces lazy states as a generalization of classically correlated states, providing necessary and sufficient conditions for zero entropy rate under any Hamiltonian interaction.

Findings

Lazy states are a broader class than classically correlated states.

Quantum correlations set bounds on the entropy rate.

Method to estimate dissipation rates in non-Markovian systems.

Abstract

We find the necessary and sufficient conditions for the entropy rate of the system to be zero under any system-environment Hamiltonian interaction. We call the class of system-environment states that satisfy this condition lazy states. They are a generalization of classically correlated states defined by quantum discord, but based on projective measurements of any rank. The concept of lazy states permits the construction of a protocol for detecting global quantum correlations using only local dynamical information. We show how quantum correlations to the environment provide bounds to the entropy rate, and how to estimate dissipation rates for general non-Markovian open quantum systems.