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arXiv · 2507.13156

Preheated inflation

Diogo S. Gorgulho·João G. Rosa
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Abstract

We propose a new mechanism of non-thermal particle production during inflation based on a narrow parametric resonance, akin to the dynamics of post-inflationary preheating. The mechanism is based on the production of scalar particles with a mass that is an oscillating function of the slowly-rolling inflaton field. This is achieved in a scenario for the collective spontaneous breaking of a U(1) gauge symmetry that, while originally proposed in the context of warm inflation, leads to non-equilibrium particle production sustaining a (sub-dominant) non-thermal radiation bath throughout inflation. We show that this may leave an observational imprint, namely oscillatory features in the primordial curvature power spectrum alongside a (mild) resonant enhancement of its amplitude, as well as secondary gravitational waves that can be probed with future CMB experiments.

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Diogo S. Gorgulho, João G. Rosa. 2025-07-17. Preheated inflation. https://arxiv.org/abs/2507.13156

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