Abstract
In this paper we study the general features of the Dyson equation at finite temperature. For a relatively long-lifetime quasiparticle, we prove that its causal Green’s function with Feynman-Dyson expansion can be put in a much simplified form. Application to the infrared absorption at crystal surfaces is discussed.
- Received 5 February 1992
DOI:https://doi.org/10.1103/PhysRevB.46.2628
©1992 American Physical Society