Ohmic Reservoir-based non-Markovianity and Quantum Speed Limit Time

• Published in: arXiv.org 2020-07
• Main Authors: Hong-Mei, Zou, Liu, Rongfang, Long, Dan, Yang, Jianhe, Lin, Danping
• Format: Article
• Language: English
• Subjects: Coupling; Dynamics; Parameters; Reservoirs; Speed limits
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2003.09774

We study the non-Markovianity and quantum speedup of a two-level atom (quantum system of interest) in a dissipative Jaynes-Cumming model, where the atom is embedded in a single-mode cavity, which is leaky being coupled to an external reservoir with Ohmic spectral density. We obtain the non-Markovianity characterized by using the probability of the atomic excited state and the negative decoherence rate in the time-local master equation. We also calculate the quantum speed limit time (QSLT) of the evolution process of the atom. The results show that, the atom-cavity coupling is the main physical reasons of the transition from Markovian to non-Markovian dynamics and the transition from no speedup to speedup process, and the critical value of this sudden transition only depends on the Ohmicity parameter. The atom-cavity coupling and the appropriate reservoir parameters can effectively improve the non-Markovianity in the dynamics process and speed up the evolution of the atom. Moreover, the initial non-Markovian dynamics first turns into Markovian and then back to non-Markovian with increasing the atom-cavity coupling under certain condition. Finally, the physical interpretation is provided.