Evolution of coupled scalar perturbations through smooth reheating. Part I. Dissipative regime
Year: 2024
Type: article
Abstract: If the inflaton is a heavy scalar field, it may equilibrate slower than some other degrees of freedom, e.g. non-Abelian gauge bosons. In this case, perturbations in the inflaton field and in a thermal plasma coexist from a given moment onwards. We derive a gauge-invariant set of three coupled equations governing the time evolution of such a system. Despite singular coefficients, a reliable numerical solution can be obtained for a long time period, starting from phase oscillations inside the Hubble horizon, and extending until acoustic oscillations in a radiation-dominated universe. Benchmarks are illustrated from a “weak regime”, where perturbations have a quantum-mechanical origin but get dissipated by interactions with the plasma. Among applications of our formalism could be inhomogeneity-induced nucleations in post-inflationary phase transitions, and the production of scalar-induced gravitational waves.
Authors: M. Laine, S. Procacci, A. Rogelj
Institutions: University of Bern, University of Geneva
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,135
OpenAlex ID: W4403425629