A formally exact one-frequency-only Bethe-Salpeter-like equation. Similarities and differences between GW +BSE and self-consistent RPA
Chemical Physics
2019-03-18 v2 Other Condensed Matter
Nuclear Theory
Abstract
A formally exact Bethe-Salpeter-like equation for the linear-response function is introduced with a kernel which depends only on the one frequency of the applied field. This is in contrast with the standard Bethe-Salpeter equation (BSE) which involves multiple-frequency integrals over the kernel and response functions. From the one-frequency kernel, known approximations are straightforwardly recovered. However, the present formalism lends itself to more powerful approximations. This is demonstrated with the exact analytical solution of the Hubbard molecule. Similarities and differences of the +BSE approach with the self-consistent random-phase approximation (RPA) is also discussed.
Keywords
Cite
@article{arxiv.1812.08421,
title = {A formally exact one-frequency-only Bethe-Salpeter-like equation. Similarities and differences between GW +BSE and self-consistent RPA},
author = {Valerio Olevano and Julien Toulouse and Peter Schuck},
journal= {arXiv preprint arXiv:1812.08421},
year = {2019}
}