[PDF] Quantum statistical mechanics Kadanoff L.P., Baym G.

These lectures are devoted to a discussion of the use of thermo- dynamic Green’s functions in describing the properties of many- particle systems. These functions provide a method for discussing finite-temperature problems with no more conceptual difficulty than ground-state (i.e., zero-temperature) problems; the method is equally applicable to boson and fermion systems, equilibrium and nonequilibrium problems.