Spatially Modulated Vacua in a Lorentz-invariant Scalar Field Theory
Abstract
Spatial modulation has been studied for a long time in condensed matter, nuclear matter and quark matter, so far in non-relativistic field theories. In this paper, spatially modulated vacua at zero temperature and zero density are studied in relativistic field theories. We first propose an adaptation of the Nambu-Goldstone theorem to higher derivative theories under the assumption of the absence of ghosts: when a global symmetry is spontaneously broken due to vacuum expectation values of space-time derivatives of fields, a Nambu-Goldstone (NG) boson appears without a canonical kinetic (quadratic derivative) term with a quartic derivative term in the modulated direction while a Higgs boson appears with a canonical kinetic term. We demonstrate this in a simple model allowing (meta)stable modulated vacuum of a phase modulation (Fulde-Ferrell state), where an NG mode associated with spontaneously broken translational and symmetries appears.
Keywords
Cite
@article{arxiv.1706.02938,
title = {Spatially Modulated Vacua in a Lorentz-invariant Scalar Field Theory},
author = {Muneto Nitta and Shin Sasaki and Ryo Yokokura},
journal= {arXiv preprint arXiv:1706.02938},
year = {2018}
}
Comments
20 pages, 3 figures, title changed, published version