Hopf term induced by fermions
High Energy Physics - Theory
2009-10-31 v2 Condensed Matter
Abstract
We derive an effective action for Dirac fermions coupled to O(3) non-linear sigma-model (NLSM) through the Yukawa-type interaction. The nonperturbative (global) quantum anomaly of this model results in a Hopf term for the effective NLSM. We obtain this term using the ``embedding'' of the CP model into the CP generalization of the model which makes the quantum anomaly perturbative. This perturbative anomaly is calculated by means of a gradient expansion of a fermionic determinant and is given by the Chern-Simons term for an auxiliary gauge field.
Keywords
Cite
@article{arxiv.hep-th/0005150,
title = {Hopf term induced by fermions},
author = {Alexander G. Abanov},
journal= {arXiv preprint arXiv:hep-th/0005150},
year = {2009}
}
Comments
5 pages, no figures, latex, elsart.cls, minor errors are corrected