Interferometric Approach to Open Quantum Systems and Non-Markovian Dynamics

TL;DR

This paper introduces a novel interferometric method to analyze and control non-Markovian dynamics in open quantum systems, revealing how interference and measurement influence memory effects and system-environment interactions.

Contribution

It presents the concept of an open system interferometer that combines interferometry with open quantum system dynamics, enabling control and probing of non-Markovian effects.

Findings

Path-wise polarization dephasing is Markovian inside the interferometer.

Interference can induce or suppress non-Markovian memory effects.

Measuring the photon path can create or destroy non-Markovianity.

Abstract

We combine the dynamics of open quantum systems with interferometry and interference introducing the concept of open system interferometer. By considering a single photon in a Mach-Zehnder interferometer, where the polarization (open system) and frequency (environment) of the photon interact, we theoretically show how inside the interferometer path-wise polarization dephasing dynamics is Markovian while the joint dynamics displays non-Markovian features. Outside the interferometer and due to interference, the open system displays rich dynamical features with distinct alternatives: Only one path displaying non-Markovian memory effects, both paths individually displaying them, or no memory effects appearing at all. Our results also illustrate that measuring the photon's path can either create or destroy non-Markovian memory effects depending on whether the measurement takes place in or outside the interferometer. Moreover, the scheme allows to probe the optical path difference inside the interferometer by studying non-Markovianity outside the interferometer. With our framework and interference, it is also possible to introduce dissipative features for the open system dynamics even though the system-environment interaction itself contains only dephasing. In general, the results open so far unexplored avenues to control open system dynamics and for fundamental studies of quantum physics.