Quantum Zeno effect and non-Markovianity in a three-level system

TL;DR

This paper investigates how the quantum Zeno effect can be used to control non-Markovian memory effects in a three-level quantum system interacting with a structured environment, revealing non-monotonic behaviors and long-lasting memory effects.

Contribution

It introduces a method to engineer dissipation and memory effects via coherent control without altering the environment or system-reservoir interaction.

Findings

Memory effects exhibit non-monotonic behavior with increasing Zeno effect strength.

A new source of long-lasting non-Markovianity is identified.

Control of coherent coupling enables engineering of dissipation and memory effects.

Abstract

We study the coexistence of the quantum Zeno effect and non-Markovianity for a system decaying in a structured bosonic environment and subject to a control field. The interaction with the environment induces decay from the excited to the ground level, which, in turn, is coherently coupled to another meta-stable state. The control of the strength of the coherent coupling between the stable levels allows the engineering of both the dissipation and of the memory effects, without modifying neither the system-reservoir interaction, nor environmental properties. We use this framework in two different parameter regimes corresponding to fast (bad cavity limit) and slow dissipation (good cavity limit) in the original, un-controlled qubit system. Our results show a non-monotonic behavior of memory effects when increasing the effectiveness of the Zeno-like freezing. Moreover, we identify a new source of memory effects which allows the persistence of non-Markovianity for long times while the excited state has already been depleted.