Dispersion relations of Nambu-Goldstone modes at finite temperature and density

Tomoya Hayata, Yoshimasa Hidaka

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


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 the expectation values of a charge density and a local operator that break the same symmetry coexist.

Original languageEnglish
Article number056006
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number5
Publication statusPublished - 2015 Mar 25
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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