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arXiv · 1010.5025

The Accuracy of Perturbative Master Equations

Chris H. Fleming·Nick I. Cummings
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Abstract

We consider open quantum systems with dynamics described by master equations that have perturbative expansions in the system-environment interaction. We show that, contrary to intuition, full-time solutions of order-2n accuracy require an order-(2n+2) master equation. We give two examples of such inaccuracies in the solutions to an order-2n master equation: order-2n inaccuracies in the steady state of the system and order-2n positivity violations, and we show how these arise in a specific example for which exact solutions are available. This result has a wide-ranging impact on the validity of coupling (or friction) sensitive results derived from second-order convolutionless, Nakajima-Zwanzig, Redfield, and Born-Markov master equations.

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Chris H. Fleming, Nick I. Cummings. 2010-10-25. The Accuracy of Perturbative Master Equations. https://doi.org/10.1103/physreve.83.031117

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