Discretized Thermal Green's Functions
Abstract
We present a spectral weight conserving formalism for Fermionic thermal Green's functions that are discretized in imaginary time and thus periodic in imaginary ("Matsubara") frequency. The formalism requires a generalization of the Dyson equation and the Baym-Kadanoff-Luttinger-Ward functional for the free energy. A conformal transformation is used to analytically continue the periodized Matsubara Green's function to the continuous real axis in a way that conserves the discontinuity at t=0 of the corresponding real-time Green's function. For given discretization the method allows numerical Green's function calculations of very high precision and it appears to give a well controlled convergent approximation as we decrease the discretization interval. The ideas are tested on Dynamical Mean Field Theory calculations of the paramagnetic Hubbard model.
Cite
@article{arxiv.1103.3516,
title = {Discretized Thermal Green's Functions},
author = {Mats Granath and Andro Sabashvili and Hugo U. R. Strand and Stellan Östlund},
journal= {arXiv preprint arXiv:1103.3516},
year = {2012}
}