Memory effects in multipartite systems coupled by nondiagonal dephasing mechanisms

Abstract

The developing of (non-Markovian) memory effects strongly depends on the underlying system-environment dynamics. Here we study this problem in multipartite arrangements where all subsystems are coupled to each other by dephasing mechanisms that are taken into account through an underlying Markovian Lindblad dynamics characterized by a nondiagonal rate matrix. Taking as system and environment arbitrary sets of complementary subsystems, it is shown that both operational and nonoperational approaches to quantum non-Markovianity can be characterized in an exact analytical way. Similarly to previous studies about dissipative entanglement generation in this kind of dynamics [Seif, Wang, and Clerk, Phys. Rev. Lett. 128, 070402 (2022)0031-900710.1103/PhysRevLett.128.070402], we found that memory effects can only emerge when a time-reversal symmetry is broken. Nevertheless, it is also found that departures from Markovianity can equivalently be represented through a statistical mixture of Markovian dephasing dynamics, which does not involve any system-environment entanglement. Specific bipartite and multipartite dynamics exemplify the main general results.