Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution
Abstract Axion inflation coupled to Abelian gauge fields via a Chern-Simons-like term of the form ϕF F ~ $$ \phi F\overset{\sim }{F} $$ represents an attractive inflationary model with a rich phenomenology, including the production of magnetic fields, black holes, gravitational waves, and the matter...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-11-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP11(2023)183 |
| _version_ | 1797199711830016000 |
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| author | Richard von Eckardstein Marco Peloso Kai Schmitz Oleksandr Sobol Lorenzo Sorbo |
| author_facet | Richard von Eckardstein Marco Peloso Kai Schmitz Oleksandr Sobol Lorenzo Sorbo |
| author_sort | Richard von Eckardstein |
| collection | DOAJ |
| description | Abstract Axion inflation coupled to Abelian gauge fields via a Chern-Simons-like term of the form ϕF F ~ $$ \phi F\overset{\sim }{F} $$ represents an attractive inflationary model with a rich phenomenology, including the production of magnetic fields, black holes, gravitational waves, and the matter-antimatter asymmetry. In this work, we focus on a particular regime of axion inflation, the so-called Anber-Sorbo (AS) solution, in which the energy loss in the gauge-field production provides the dominant source of friction for the inflaton motion. We revisit the AS solution and confirm that it is unstable. Contrary to earlier numerical works that attempted to reach the AS solution starting from a regime of weak backreaction, we perform, for the first time, a numerical evolution starting directly from the regime of strong backreaction. Our analysis strongly suggests that, at least as long as one neglects spatial inhomogeneities in the inflaton field, the AS solution has no basin of attraction, not even a very small one that might have been missed in previous numerical studies. Our analysis employs an arsenal of analytical and numerical techniques, some established and some newly introduced, including (1) linear perturbation theory along the lines of ref. [1], (2) the gradient expansion formalism (GEF) developed in ref. [2], (3) a new linearized version of the GEF, and (4) the standard mode-by-mode approach in momentum space in combination with input from the GEF. All these methods yield consistent results confirming the instability of the AS solution, which renders the dynamics of axion inflation in the strong-backreaction regime even more interesting than previously believed. |
| first_indexed | 2024-03-09T15:32:33Z |
| format | Article |
| id | doaj.art-cd49900a0ed14d2ea9f8a961ce1453f4 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-04-24T07:20:06Z |
| publishDate | 2023-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-cd49900a0ed14d2ea9f8a961ce1453f42024-04-21T11:05:23ZengSpringerOpenJournal of High Energy Physics1029-84792023-11-0120231114210.1007/JHEP11(2023)183Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solutionRichard von Eckardstein0Marco Peloso1Kai Schmitz2Oleksandr Sobol3Lorenzo Sorbo4Institute for Theoretical Physics, University of MünsterDipartimento di Fisica e Astronomia “Galileo Galilei”, Università degli Studi di PadovaInstitute for Theoretical Physics, University of MünsterInstitute for Theoretical Physics, University of MünsterAmherst Center for Fundamental Interactions, Department of Physics, University of MassachusettsAbstract Axion inflation coupled to Abelian gauge fields via a Chern-Simons-like term of the form ϕF F ~ $$ \phi F\overset{\sim }{F} $$ represents an attractive inflationary model with a rich phenomenology, including the production of magnetic fields, black holes, gravitational waves, and the matter-antimatter asymmetry. In this work, we focus on a particular regime of axion inflation, the so-called Anber-Sorbo (AS) solution, in which the energy loss in the gauge-field production provides the dominant source of friction for the inflaton motion. We revisit the AS solution and confirm that it is unstable. Contrary to earlier numerical works that attempted to reach the AS solution starting from a regime of weak backreaction, we perform, for the first time, a numerical evolution starting directly from the regime of strong backreaction. Our analysis strongly suggests that, at least as long as one neglects spatial inhomogeneities in the inflaton field, the AS solution has no basin of attraction, not even a very small one that might have been missed in previous numerical studies. Our analysis employs an arsenal of analytical and numerical techniques, some established and some newly introduced, including (1) linear perturbation theory along the lines of ref. [1], (2) the gradient expansion formalism (GEF) developed in ref. [2], (3) a new linearized version of the GEF, and (4) the standard mode-by-mode approach in momentum space in combination with input from the GEF. All these methods yield consistent results confirming the instability of the AS solution, which renders the dynamics of axion inflation in the strong-backreaction regime even more interesting than previously believed.https://doi.org/10.1007/JHEP11(2023)183Axions and ALPsEarly Universe Particle Physics |
| spellingShingle | Richard von Eckardstein Marco Peloso Kai Schmitz Oleksandr Sobol Lorenzo Sorbo Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution Journal of High Energy Physics Axions and ALPs Early Universe Particle Physics |
| title | Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution |
| title_full | Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution |
| title_fullStr | Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution |
| title_full_unstemmed | Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution |
| title_short | Axion inflation in the strong-backreaction regime: decay of the Anber-Sorbo solution |
| title_sort | axion inflation in the strong backreaction regime decay of the anber sorbo solution |
| topic | Axions and ALPs Early Universe Particle Physics |
| url | https://doi.org/10.1007/JHEP11(2023)183 |
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