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Cutting rules in the real time formalisms at finite temperature

Francois Gelis
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Abstract

In this paper, we review the set of rules specific to the calculation of the imaginary part of a Green's function at finite temperature in the real-time formalisms. Emphasis is put on the clarification of a recent controversy concerning these rules in the "1/2" formalism, more precisely on the issue related to the interpretation of these rules in terms of cut diagrams, like at T=0. On the second hand, new results are presented, enabling one to calculate the imaginary part of thermal Green's functions in other formulations of the real-time formalism, like the "retarded/advanced" formalism in which a lot of simplifications occur.

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Francois Gelis. 1997-01-29. Cutting rules in the real time formalisms at finite temperature. https://doi.org/10.1016/s0550-3213(97)00511-7

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