Convergent methods for calculating thermodynamic Green functions
Samuel P. Bowen, Clayton D. Williams, Jay D. Mancini
A convergent method of approximating thermodynamic Green functions is outlined briefly. The method constructs a sequence of approximants which converges independently of the strength of the Hamiltonian's coupling constants. Two new concepts associated with the approximants are introduced: the resolving power of the approximation, and conditional creation (annihilation) operators. These ideas are illustrated on an exactly soluble model and a numerical example. A convergent expression for the scattering rate in a field theory is also derived.
Physical Review A•Aug 1, 1984•5 citations