Distinguishing between quantum and classical Markovian dephasing dissipation

TL;DR

This paper establishes criteria to distinguish quantum from classical Markovian dephasing in open quantum systems, emphasizing the role of time-reversal symmetry and bath susceptibilities in entanglement generation.

Contribution

It provides a sufficient condition for quantum dissipation based on entanglement and introduces an experimental protocol to identify truly quantum dephasing.

Findings

Broken time-reversal symmetry is necessary for dissipative entanglement.

Nonzero bath susceptibilities alone do not guarantee quantum dissipation.

An explicit protocol for experimental identification of quantum dephasing dissipation.

Abstract

Understanding whether dissipation in an open quantum system is truly quantum is a question of both fundamental and practical interest. We consider n qubits subject to correlated Markovian dephasing and present a sufficient condition for when bath-induced dissipation can generate system entanglement and hence must be considered quantum. Surprisingly, we find that the presence or absence of time-reversal symmetry plays a crucial role: broken time-reversal symmetry is required for dissipative entanglement generation. Further, simply having nonzero bath susceptibilities is not enough for the dissipation to be quantum. We also present an explicit experimental protocol for identifying truly quantum dephasing dissipation and lay the groundwork for studying more complex dissipative systems and finding optimal noise mitigating strategies.