Preservation of Quantum Coherence for Gaussian-State Dynamics in a Non-Markovian Process**Supported by the National Natural Science Foundation of China under Grant Nos 11405100, 11404377 and 11674360, the Natural Science Basic Research Plan of Shaanxi Province of China under Grant No 2015JM1032, and the Doctoral Research Fund of Shaanxi University of Science and Technology of China under Grant No 2018BJ-02.

Abstract

Coherence is a key resource in quantum information science. Exactly understanding and controlling the variation of coherence are vital for implementation in realistic quantum systems. Using P-representation of density matrix, we obtain the analytical solution of the master equation for the classical states in the non-Markovian process and investigate the coherent dynamics of Gaussian states. It is found that quantum coherence can be preserved in such a process if the coupling strength between system and environment exceeds a threshold value. We also discuss the characteristic function of the Gaussian states in the non-Markovian process, which provides an inevitable bridge for the control and operation of quantum coherence.