Systematic non-perturbative approach to quantum non-Markovian dynamics
Last updated March 29, 2019 by Alessandro Ferraro
Wednesday, March 27th 2019, 04:00 PM, MAPTC/0G/006
Speaker: A. Smirne (Ulm University).
I will present a general nonperturbative approach to non-Markovian dynamics, which consists in dividing the influence of the environment on the open system into a non-Markovian core, which encloses all the memory effects during the evolution, and a further Markovian component, representing the unidirectional leakage of information out of the non-Markovian core. The method is built on an equivalence theorem, recently derived in , which proves that a Gaussian bosonic environment evolving unitarily can be replaced by a Gaussian bosonic environment undergoing a Lindblad dynamics without changing the reduced dynamics of the open system interacting with it, if the first moments and the two-time correlation functions of the original and the auxiliary baths are the same at all times. Noticeably, as a special case, one recovers the well-known pseudomodes approach , directly extending it to a different form of the coupling. Starting from this result, a systematic procedure can be developed  to formulate auxiliary effective environments consisting of few bosonic degrees of freedom, typically a network of interacting harmonic oscillators, in this way reducing strongly the complexity of the model under study and then allowing for an efficient numerical investigation of the dynamics.
 D. Tamascelli, A. Smirne, S.F. Huelga, and M.B. Plenio, Nonperturbative Treatment of non-Markovian Dynamics of Open Quantum Systems, Phys. Rev. Lett. 120, 030402 (2018).
 B. M. Garraway, Nonperturbative decay of an atomic system in a cavity, Phys. Rev. A 55, 2290 (1997).
 F. Mascherpa, A. Smirne, P. Fernandez Acebal, S. Donadi, D. Tamascelli, S.F. Huelga, and M.B. Plenio, in preparation.
We are a Research Cluster of the School of Mathematics and Physics at Queen’s University Belfast in Northern Ireland. Our research interests are focused primarily on computational and theoretical physics.
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