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arXiv · 1706.02938

Spatially Modulated Vacua in a Lorentz-invariant Scalar Field Theory

Muneto Nitta·Shin Sasaki·Ryo Yokokura
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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 $U(1)$ symmetries appears.

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Muneto Nitta, Shin Sasaki, Ryo Yokokura. 2018-09-20. Spatially Modulated Vacua in a Lorentz-invariant Scalar Field Theory. https://doi.org/10.1140/epjc%2Fs10052-018-6235-9

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