Kinetic Gauge Friction in Natural Inflation

Autor:	Michelotti, Martino, Quaglia, Rodrigo Gonzalez, Dimastrogiovanni, Ema, Fasiello, Matteo, Roest, Diederik
Rok vydání:	2024
Předmět:	Astrophysics - Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory
Druh dokumentu:	Working Paper
Popis:	We study an extension of the natural inflation model comprising a non-Abelian gauge sector coupled to the axion-inflaton kinetic term. We show how such non-minimal coupling serves as a source of friction for the rolling inflaton granting sixty or more $e$-folds of accelerated expansion for sub-Planckian values of the axion decay constant. The analysis of perturbations reveals a negative sound speed, thus signaling an instability. Implementing a Chern-Simons-type coupling between the inflaton and gauge sectors cures the instability by delivering a positive speed. We perform a numerical study of scalar and tensor perturbations for a fiducial set of parameters finding that the corresponding observables are compatible with current CMB bounds. Comment: 24 pages, 8 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/2411.19892 Zobrazit plný text záznamu View this record from Arxiv