2012/07/31 by F. Ciccarello, G. M. Palma, V. Giovannetti · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physreva.87.040103
published as Phys. Rev. A 87, 040103(R) (2013) · 5+1 pages, 2 figures
arxiv created 2013/04/27 · arxiv updated 2013/04/30
We present a theoretical framework to tackle quantum non-Markovian dynamics based on a microscopic collision model (CM), where the bath consists of a large collection of initially uncorrelated ancillas. Unlike standard memoryless CMs, we endow the bath with memory by introducing inter-ancillary collisions between next system-ancilla interactions. Our model interpolates between a fully Markovian dynamics and the continuous interaction of the system with a single ancilla, i.e., a strongly non-Markovian process. We show that in the continuos limit one can derive a general master equation, which while keeping such features is guaranteed to describe an unconditionally completely positive and trace-preserving dynamics. We apply our theory to an atom in a dissipative cavity for a Lorentzian spectral density of bath modes, a dynamics which can be exactly solved. The predicted evolution shows a significant improvement in approaching the exact solution with respect to two well-known memory-kernel master equations.