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

• Published in: Scientific reports Vol. 6; no. 1; p. 39061
• Main Authors: Karlsson, Antti, Francica, Francesco, Piilo, Jyrki, Plastina, Francesco
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20.12.2016; Nature Publishing Group
• Subjects: 639/766/483/1139; 639/766/483/640; Approximation; Coexistence; Freezing; Humanities and Social Sciences; multidisciplinary; Physics; Science
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep39061

We study the coexistence of the quantum Zeno-type 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 and 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.