Condensed matter theory
Kubo-Martin-Schwinger relation for an interacting mobile impurity
Shifting time by a factor of temperature lets us equate certain Green’s functions in quantum field theory. This is the famous Kubo-Martin-Schwinger relation (KMS). We consider finite temperature correlation functions for an interacting mobile impurity in the Yang-Gaudin model, and study injection/ejection Green’s functions. These are, in fact, related by a refinement of KMS, which is valid for every value of the so-called spin rapidity.