20–25 Aug 2023
Universität Hamburg
Europe/Berlin timezone

Gravitational wave background from vacuum and thermal fluctuations during axion-like inflation

23 Aug 2023, 16:50
20m
Hörsaal C (Historic main building)

Hörsaal C

Historic main building

Edmund-Siemers-Allee 1
Parallel session talk Gravitation and Cosmology T02 Gravitation and Cosmology

Speaker

Philipp Klose (Bern University)

Description

We revisit the framework of axion-like inflation, considering a warm inflation scenario in which the inflaton couples to the topological charge density of non-Abelian gauge bosons whose self-interactions result in a rapidly thermalizing heat bath. Including both dispersive (mass) and absorptive (friction) effects, we find that the system remains in a weak regime of warm inflation (thermal friction Hubble rate) for phenomenologically viable parameters. We derive an interpolating formula for vacuum and thermal production of tensor perturbations in generic warm inflation scenarios, and find that the perturbations exhibit a model-independent f^3 frequency shape in the LISA window, with a coefficient that measures the maximal shear viscosity of the thermal epoch.

Collaboration / Activity Bern University

Primary authors

Prof. Mikko Laine (Bern University) Philipp Klose (Bern University) Simona Procacci (Bern University)

Presentation materials