2007/01/31 by Philipp Werner, Andrew J. Millis · 2 citations
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.99.146404
published as Phys. Rev. Lett. 99, 146404 (2007) · Published version
arxiv created 2007/10/04 · arxiv updated 2009/12/01
We present a method for solving impurity models with electron-phonon coupling, which treats the phonons efficiently and without approximations. The algorithm is applied to the Holstein-Hubbard model in the dynamical mean field approximation, where it allows access to strong interactions, very low temperatures and arbitrary fillings. We show that a renormalized Migdal-Eliashberg theory provides a reasonlable description of the phonon contribution to the electronic self energy in strongly doped systems, but fails if the quasiparticle energy becomes of order of the phonon frequency.