2025/07/17 by Gorgulho, Diogo S., Rosa, João G.
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2507.13156
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.