PhysRevX.10.041024.pdf (631.69 kB)
Download fileCorrelation-picture approach to open-quantum-system dynamics
journal contribution
posted on 2020-11-18, 16:36 authored by S Alipour, AT Rezakhani, AP Babu, K Mølmer, M Möttönen, Tapio Ala-NissilaTapio Ala-NissilaWe introduce a dynamical picture, referred to as correlation picture, which connects a correlated bipartite state to its uncorrelated counterpart. This picture allows us to derive an exact dynamical equation for a general open-system dynamics with system-environment correlations included. This exact dynamics is in the form of a Lindblad-like equation even in the presence of initial system-environment correlations. For explicit calculations, we also develop a weak-correlation expansion that allows us to introduce systematic perturbative approximations. This expansion provides approximate master equations that can feature advantages over existing weak-coupling techniques. As a special case, we derive a Markovian master equation, which is different from existing approaches. We compare our equations with corresponding standard weak-coupling equations using two examples, for which our correlation-picture formalism is more accurate, or at least as accurate as the weak-coupling equations.
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