Pseudomodes as an effective description of memory: Non-Markovian dynamics of two-state systems in structured reservoirs

We investigate the non-Markovian dynamics of two-state systems in structured reservoirs. We establish a connection between two theoretical quantum approaches, the pseudomodes [ B. M. Garraway Phys. Rev. A 55 2290 (1997)] and the recently developed non-Markovian quantum jump method [ J. Piilo et al. Phys. Rev. Lett. 100 180402 (2008)]. This connection provides a clear physical picture of how the structured reservoir affects the system dynamics, suggesting the role of the pseudomodes as effective description of environmental memory.