Inflation without an inflaton
We propose a novel scenario in which scalar perturbations, which seed the large-scale structure of the universe, are generated without relying on a scalar field (the inflaton). In this framework, inflation is driven by a de Sitter space time, where tensor metric fluctuations (i.e., gravitational wav...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2025-07-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/vfny-pgc2 |
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| _version_ | 1850117112706629632 |
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| author | Daniele Bertacca Raul Jimenez Sabino Matarrese Angelo Ricciardone |
| author_facet | Daniele Bertacca Raul Jimenez Sabino Matarrese Angelo Ricciardone |
| author_sort | Daniele Bertacca |
| collection | DOAJ |
| description | We propose a novel scenario in which scalar perturbations, which seed the large-scale structure of the universe, are generated without relying on a scalar field (the inflaton). In this framework, inflation is driven by a de Sitter space time, where tensor metric fluctuations (i.e., gravitational waves) naturally arise from quantum vacuum oscillations, and scalar fluctuations are generated via second-order tensor effects. We compute the power spectrum of such scalar fluctuations and show it to be consistent with near scale invariance. We derive the necessary conditions under which scalar perturbations become significant and much larger than the tensor modes, and we identify a natural mechanism to end inflation via a transition to a radiation-dominated phase. Our proposed mechanism could remove the need for a model-dependent scenario: the choice of a scalar field, as the inflaton, to drive inflation. |
| format | Article |
| id | doaj-art-9e47dab350ce43bb84957f8f2ceb7789 |
| institution | OA Journals |
| issn | 2643-1564 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj-art-9e47dab350ce43bb84957f8f2ceb77892025-08-20T02:36:09ZengAmerican Physical SocietyPhysical Review Research2643-15642025-07-0173L03201010.1103/vfny-pgc2Inflation without an inflatonDaniele BertaccaRaul JimenezSabino MatarreseAngelo RicciardoneWe propose a novel scenario in which scalar perturbations, which seed the large-scale structure of the universe, are generated without relying on a scalar field (the inflaton). In this framework, inflation is driven by a de Sitter space time, where tensor metric fluctuations (i.e., gravitational waves) naturally arise from quantum vacuum oscillations, and scalar fluctuations are generated via second-order tensor effects. We compute the power spectrum of such scalar fluctuations and show it to be consistent with near scale invariance. We derive the necessary conditions under which scalar perturbations become significant and much larger than the tensor modes, and we identify a natural mechanism to end inflation via a transition to a radiation-dominated phase. Our proposed mechanism could remove the need for a model-dependent scenario: the choice of a scalar field, as the inflaton, to drive inflation.http://doi.org/10.1103/vfny-pgc2 |
| spellingShingle | Daniele Bertacca Raul Jimenez Sabino Matarrese Angelo Ricciardone Inflation without an inflaton Physical Review Research |
| title | Inflation without an inflaton |
| title_full | Inflation without an inflaton |
| title_fullStr | Inflation without an inflaton |
| title_full_unstemmed | Inflation without an inflaton |
| title_short | Inflation without an inflaton |
| title_sort | inflation without an inflaton |
| url | http://doi.org/10.1103/vfny-pgc2 |
| work_keys_str_mv | AT danielebertacca inflationwithoutaninflaton AT rauljimenez inflationwithoutaninflaton AT sabinomatarrese inflationwithoutaninflaton AT angeloricciardone inflationwithoutaninflaton |