Interference between lossy quantum evolutions activates information backflow
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.
Cite
@article{arxiv.2507.22150,
title = {Interference between lossy quantum evolutions activates information backflow},
author = {Sutapa Saha and Ujjwal Sen},
journal= {arXiv preprint arXiv:2507.22150},
year = {2025}
}
Comments
11 pages, 5 figures