Kinetic gauge friction in natural inflation
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-Plancki...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:dnet:digitalcsic_::1c73b1215cefc4bdbff961d01ff59891 |
| Acceso en línea: | http://hdl.handle.net/10261/428820 https://www.scopus.com/pages/publications/105003373506?origin=resultslist |
| Access Level: | acceso abierto |
| Palabra clave: | axions cosmological perturbation theory inflation primordial gravitational waves (theory) |
| Sumario: | 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 squared, 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. © 2025 The Author(s) |
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