Dispersion relations of Nambu-Goldstone modes at finite temperature and density
Abstract
We discuss the dispersion relations of Nambu-Goldstone (NG) modes associated with spontaneous breaking of internal symmetries at finite temperature and/or density. We show that the dispersion relations of type-A (I) and type-B (II) NG modes are linear and quadratic in momentum, whose imaginary parts are quadratic and quartic, respectively. In both cases, the real parts of the dispersion relations are larger than the imaginary parts when the momentum is small, so that the NG modes can propagate far away. We derive the gap formula for NG modes in the presence of a small explicit breaking term. We also discuss the gapped partners of type-B NG modes, when type-A and type-B NG modes coexist.
Keywords
Cite
@article{arxiv.1406.6271,
title = {Dispersion relations of Nambu-Goldstone modes at finite temperature and density},
author = {Tomoya Hayata and Yoshimasa Hidaka},
journal= {arXiv preprint arXiv:1406.6271},
year = {2015}
}
Comments
32 pages, no figure; typos corrected, some discussions elaborated in Sec. VB5