Two-qubit non-Markovianity induced by a common environment

TL;DR

This paper investigates how a common environment can induce non-Markovian behavior in two-qubit systems, revealing the physical mechanisms and implications for quantum information flow.

Contribution

It demonstrates that a common reservoir can induce non-Markovianity and identifies its physical origin, linking it to non-divisibility of the dynamical map and resource potential.

Findings

Non-Markovianity can be induced by a common reservoir.

Non-Markovianity coincides with non-divisibility of the dynamical map.

The measure of non-Markovianity has potential as a resource in multipartite systems.

Abstract

We study non-Markovianity as backflow of information in two-qubit systems. We consider a setting where, by changing the distance between the qubits, one can interpolate between independent reservoir and common reservoir scenarios. We demonstrate that non-Markovianity can be induced by the common reservoir and single out the physical origin of this phenomenon. We show that two-qubit non-Markovianity coincides with instances of non-divisibility of the corresponding dynamical map, and we discuss the pair of states maximizing information flowback. We also discuss the issue of additivity for the measure we use and in doing so, give an indication of its usefulness as a resource for multipartite quantum systems.