D01.00009. Generalized theory of pseudomodes for exact descriptions of non-Markovian quantum processes
Presented by: Graeme Pleasance
In this talk we develop a general approach to analyzing the non-Markovian behavior of an open quantum system in a setting where the interaction is modelled by a generalized class of spectral density function. By introducing an auxiliary model in which the environment is replaced by a set of discrete bosonic modes exhibiting Markovian dissipative interactions, we prove the validity of the conditions allowing for a non-Markovian open system dynamics to be amended to a Markovian description, where the dynamics in the latter is governed by an exact master equation of Lindblad form. Initially we apply our result to obtain a generalization of the pseudomode method  in cases where the spectral density function has a Lorentzian structure. For many other types of spectral density function, we extend this result to show that an open system dynamics may be modelled physically using discrete modes which admit a non-Hermitian coupling to the system, and for such cases determine the equivalent master equation to no longer be of Lindblad form. For applications involving two discrete modes, we demonstrate how to convert between pathological and Lindblad forms of the master equation via .  B. M. Garraway, Nonperturbative decay of an atomic system in a cavity, Phys. Rev. A 55, 2290 (1997).
- Graeme Pleasance
- Barry M. Garraway
- Francesco Petruccione