Correlation-Picture Approach to Open-Quantum-System Dynamics

We 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...

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Bibliographic Details
Published in:Physical review. X 2020-11, Vol.10 (4), p.041024, Article 041024
Main Authors: Alipour, S., Rezakhani, A. T., Babu, A. P., Mølmer, K., Möttönen, M., Ala-Nissila, T.
Format: Article
Language:English
Subjects:
Correlation
Coupling
Quantum computers
Quantum theory
System dynamics
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Summary:We 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.
ISSN:2160-3308
2160-3308
DOI:10.1103/PhysRevX.10.041024