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From Reversible Quantum Microdynamics to Irreversible Quantum Transport

J. Rau·B. Müller
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Abstract

The transition from reversible microdynamics to irreversible transport can be studied very efficiently with the help of the so-called projection method. We give a concise introduction to that method, illustrate its power by using it to analyze the well-known rate and quantum Boltzmann equations, and present, as a new application, the derivation of a source term accounting for the spontaneous creation of electron-positron pairs in strong fields. Thereby we emphasize the fundamental importance of time scales: only if the various time scales exhibited by the dynamics are widely disparate, can the evolution of the slower degrees of freedom be described by a conventional Markovian transport equation; otherwise, one must account for finite memory effects. We show how the projection method can be employed to determine these time scales, and how --if necessary-- it allows one to include memory effects in a straightforward manner. Finally, there is an appendix in which we discuss the concepts of entropy and macroscopic irreversibility.

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J. Rau, B. Müller. 1995-05-08. From Reversible Quantum Microdynamics to Irreversible Quantum Transport. https://doi.org/10.1016/0370-1573(95)00077-1

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