Interference between lossy quantum evolutions activates information backflow

TL;DR

This paper investigates how interference between lossy quantum evolutions can activate information backflow, revealing non-Markovian behavior and enabling information retrieval from the environment in quantum systems.

Contribution

It introduces a novel interference-based approach to activate information backflow in non-Markovian quantum evolutions, enhancing robustness and performance over previous methods.

Findings

Interference can activate information backflow in non-Markovian evolutions.

Coherently-controlled quantum operation trajectories improve performance.

The method is more robust than traditional quantum switch arrangements.

Abstract

Quantum evolutions are often non-unitary and in such cases, they are frequently regarded as lossy. Such lossiness, however, does not necessarily persist throughout the evolution, and there can often be intermediate time-spans during which information ebbs in the environment to re-flood the system -- an event known as information backflow. This phenomenon serves as a well-established and sufficient indicator of non-Markovian behavior of open quantum dynamics. Nevertheless, not all non-Markovian dynamics exhibit such backflow. We find that when interference is allowed between two quantum evolutions that individually generate non-Markovianity and yet do not exhibit information backflow, it becomes possible to retrieve information from the environment. Furthermore, we show that this setup involving coherently-controlled quantum operation trajectories provides enhanced performance and is more robust compared to an alternate coherently-controlled arrangement of the quantum switch.