|DATE||December 06 (Mon), 2021|
|TITLE||Counting Nambu-Goldstone modes of higher-form global symmetries|
|ABSTRACT||When continuous symmetries are spontaneously broken, there appear gapless modes called Nambu-Goldstone (NG) modes. Due to their gapless nature, they are important degrees of freedom at low energies. Recently, a generalized kind of symmetries, called higher-form symmetries, have been discussed, whose charged objects are extended. The analogue of the NG theorem exists, and photons can be regarded as NG modes for a spontaneously broken higher-form symmetry. In this talk, I will discuss how to count the number of NG modes associated with spontaneously broken symmetries that can include higher-form ones . I will give a formula for the number of NG modes, which is also applicable for systems without Lorentz invariance.
Reference:  Y. Hidaka, Y. Hirono, R. Yokokura, Phys. Rev. Lett. 126, 071601 (2021). [arXiv:2007.15901]