Least square based method for obtaining one-particle spectral functions from temperature Green functions

TitleLeast square based method for obtaining one-particle spectral functions from temperature Green functions
Publication TypeJournal Article
Year of Publication2013
AuthorsLiu J
Journal TitleComputer Physics Communications
Volume184
Pages367-373
Date Published02
Type of ArticleArticle
ISBN Number0010-4655
Accession NumberWOS:000311661100011
Keywordscontinuation, fermion systems, Global minimization, least square fit (NNLS), model, Non-negative, One-particle spectral function, Pade analytic, quantum monte-carlo, Temperature Green function, Tikhonov regularization
Abstract

A least square based fitting scheme is proposed to extract an optimal one-particle spectral function from any one-particle temperature Green function. It uses the existing non-negative least square (NNLS) fit algorithm to do the fit, and Tikhonov regularization to help with possible numerical singular behaviors. By flexibly adding delta peaks to represent very sharp features of the target spectrum, this scheme guarantees a global minimization of the fitted residue. The performance of this scheme is manifested with diverse physical examples. The proposed scheme is shown to be comparable in performance to the standard Pade analytic continuation scheme. (C) 2012 Elsevier B.V. All rights reserved.

URL<Go to ISI>://WOS:000311661100011
DOI10.1016/j.cpc.2012.09.019
Alternate JournalComput. Phys. Commun.