English

Gauged Wess-Zumino terms for a general coset space

High Energy Physics - Theory 2022-07-26 v3 Strongly Correlated Electrons Superconductivity High Energy Physics - Phenomenology

Abstract

The low-energy physics of systems with spontaneously broken continuous symmetry is dominated by the ensuing Nambu-Goldstone bosons. It has been known for half a century how to construct invariant Lagrangian densities for the low-energy effective theory of Nambu-Goldstone bosons. Contributions, invariant only up to a surface term -- also known as the Wess-Zumino (WZ) terms -- are more subtle, and as a rule are topological in nature. Although WZ terms have been studied intensively in theoretically oriented literature, explicit expressions do not seem to be available in sufficient generality in a form suitable for practical applications. Here we construct the WZ terms in d=1,2,3,4d=1,2,3,4 spacetime dimensions for an arbitrary compact, semisimple and simply connected symmetry group GG and its arbitrary connected unbroken subgroup HH, provided that the dd-th homotopy group of the coset space G/HG/H is trivial. Coupling to gauge fields for the whole group GG is included throughout the construction. We list a number of explicit matrix expressions for the WZ terms in four spacetime dimensions, including those for QCD-like theories, that is vector-like gauge theories with fermions in a complex, real or pseudoreal representation of the gauge group.

Keywords

Cite

@article{arxiv.1809.05310,
  title  = {Gauged Wess-Zumino terms for a general coset space},
  author = {Tomas Brauner and Helena Kolesova},
  journal= {arXiv preprint arXiv:1809.05310},
  year   = {2022}
}

Comments

19 pages; v2: the examples section substantially rewritten (a critical error corrected and a new example added), matches text published in Nucl. Phys. B; v3: the statement about de Rham cohomology of U(N)/U(N-1) coset spaces in footnote 8 corrected