Hyperfunction formulation of many body Green's functions and the Matsubara formalism
arXiv:2204.09697
Abstract
We show that the single-particle Green's functions used in many body theory have an elegant description in the form of hyperfunctions. We summarize the necessary hyperfunction concepts. We show that the analytical properties and the relations between different Green's functions are natural within this formulation. Important results from the standard formalism are recovered straightforwardly. We argue that hyperfunctions could possibly provide a powerful new tool for many body theory, if the formalism could be developed beyond single-particle Green's functions.
5 pages, 6 figures. The following article has been submitted to Journal of Mathematical Physics (AIP)