Gradient expansion approach to multiple-band Fermi liquids
Abstract
Promoted by the recent progress of Berry phase physics in spin galvanomagnetic communities, we develop a systematic derivation of the reduced Keldysh equation (RKE) which captures the low-energy dynamics of quasi-particles constrained within doubly degenerate bands forming a single Fermi surface. Specifically, we project out the fully occupied/empty band degrees of freedom perturbatively in the gradient expansion, whose coupling constant measures how a system is disequilibrated. As for the electron-electron interactions, however, we only employ the so-called adiabatic assumption of the Fermi liquid theory, so that the effect of electron correlations onto the adiabatic transport of quasi-particles, i.e. the hermitian (real) part of the self-energy, is taken into account in an unbiased manner.
Cite
@article{arxiv.0706.4251,
title = {Gradient expansion approach to multiple-band Fermi liquids},
author = {Ryuichi Shindou and Leon Balents},
journal= {arXiv preprint arXiv:0706.4251},
year = {2009}
}