出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Nonperturbative approximation schemes are inevitable even in weakly coupled theories if the
nonequilibrium behavior of quantum fields is investigated. The two-particle irreducible (2PI)
effective action formalism provides an efficient framework for obtaining resummation schemes
both in and out of equilibrium. We briefly review the these techniques and discuss recent findings
for nonequilibrium field theories.
