Detecting non-Markovianity from continuous monitoring

TL;DR

This paper presents a method to detect non-Markovian behavior in an open quantum system by analyzing continuous photon flux measurements from its environment, avoiding complex tomography.

Contribution

It introduces a measurement-based approach to identify non-Markovianity in quantum systems through continuous monitoring of the environment, linking it with pseudomode methods.

Findings

Photon flux properties reveal memory effects

Detection of non-Markovianity without tomography

Applicable to atom-cavity systems

Abstract

We study how non-Markovianity of an open two-level system can be detected when continuously monitoring a part of its bosonic environment. Considering a physical scenario of an atom in a lossy cavity, we demonstrate that the properties of the time-dependent flux of the photons from the cavity allows the detection of memory effects in the atomic dynamics, without requiring state nor process tomography. This framework overlaps with effective descriptions for the memory part of the environment using pseudomode methods. Our central results show how the Markovian measurement record on the environment of an enlarged open system allows to draw conclusions on the non- Markovianity of the original system of interest.