Detection of Bidirectional System-Environment Information Exchanges

TL;DR

This paper introduces an operational method to distinguish between bidirectional information exchange and environment-induced non-Markovianity in quantum systems, enhancing understanding of quantum memory effects.

Contribution

The authors propose a measurement-based scheme to differentiate between true bidirectional information flow and environment effects that do not involve information exchange.

Findings

Successfully detects bidirectional information flows in various non-Markovian dynamics.

Differentiates between physical information exchange and environment-induced effects.

Applicable to dissipative and dephasing quantum systems.

Abstract

Quantum memory effects can be related to a bidirectional exchange of information between an open system and its environment, which in turn modifies the state and dynamical behavior of the last one. Nevertheless, non-Markovianity can also be induced by environments whose dynamics is not affected during the system evolution, implying the absence of any physical information exchange. An unsolved open problem in the formulation of quantum memory measures is the apparent impossibility of discerning between both paradigmatic cases. Here, we present an operational scheme that, based on the outcomes of successive measurements processes performed over the system of interest, allows to distinguishing between both kinds of memory effects. The method accurately detects bidirectional information flows in diverse dissipative and dephasing non-Markovian open system dynamics.