Enhancement of non-Markovianity by interference of two reservoirs

Abstract

We study the effect of the interference between two independent non-Markovian reservoirs on the non-Markovianity of a two-level system. We find that the interference can enhance the non-Markovianity of the system. The additive master equation (ME) is invalid even if only one of the two reservoirs is non-Markovian, while it is a good approximation when all reservoirs are Markovian. We also derive the two states uniqueness for a two-level system coupled to structured reservoirs which maximize the measure of non-Markovianity defined by Breuer et al. [Phys. Rev. Lett. 103 (2009) 210401].