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arXiv · 2607.23646

Scalar-induced gravitational waves from inflation with symmetry breaking

Chong-Bin Chen·Jia-Xi Feng·Fu-Wen Shu·Linjie Song
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Abstract

We investigate scalar-induced gravitational waves (SIGWs) in an inflationary model with symmetry breaking, in which charged scalar fields are coupled to an isotropic triplet of Abelian gauge fields through a kinetic function. Such SIGWs can be enhanced to a detectable level when the mixing between the inflaton and gauge-field perturbations is sufficiently large. We find that the longitudinal mode and the charge-dependent mixing between perturbations become relevant only when the gauge-field excitation occurs sufficiently late during inflation. In this regime, the corresponding SIGWs are shifted to ultra-high frequencies, typically can around the GHz band. We show that the parameters characterizing the effects of the longitudinal mode and charge-dependent mixing affect the signal in qualitatively different ways. This provides characteristic signatures for distinguishing the neutral case from the charged one through the frequency profile of the stochastic gravitational-wave background.

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Chong-Bin Chen, Jia-Xi Feng, Fu-Wen Shu, Linjie Song. 2026-07-26. Scalar-induced gravitational waves from inflation with symmetry breaking. https://arxiv.org/abs/2607.23646

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