One-electron spectral functions of the attractive Hubbard model for intermediate coupling
We calculate the one-electron spectral function of the attractive (negative-U) Hubbard model. We work in the intermediate-coupling and low-density regime and obtain the self-energy in an approximate analytical form. The excitation spectrum is found to consist of three branches. The results are obtained in a framework based on the self-consistent T -matrix approximation, which is compatible with the Mermin-Wagner theorem.
Record created on 2015-04-21, modified on 2016-08-09