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Derivation of Transport Equations using the Time-Dependent Projection Operator Method

Tomoi Koide
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Abstract

We develop a formalism to carry out coarse-grainings in quantum field theoretical systems by using a time-dependent projection operator in the Heisenberg picture. A systematic perturbative expansion with respect to the interaction part of the Hamiltonian is given, and a Langevin-type equation without a time-convolution integral term is obtained. This method is applied to a quantum field theoretical model, and coupled transport equations are derived.

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Tomoi Koide. 2002-02-12. Derivation of Transport Equations using the Time-Dependent Projection Operator Method. https://doi.org/10.1143/ptp.107.525

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