Exponential quintessence: curved, steep and stringy?
Abstract We explore the possibility that our universe’s current accelerated expansion is explained by a quintessence model with an exponential scalar potential, V = V 0 e −λ ϕ , keeping an eye towards λ ≥ 2 $$ \sqrt{2} $$ and an open universe, favorable to a string theory realisation and with no cos...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2024-08-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP08(2024)117 |
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| author | David Andriot Susha Parameswaran Dimitrios Tsimpis Timm Wrase Ivonne Zavala |
| author_facet | David Andriot Susha Parameswaran Dimitrios Tsimpis Timm Wrase Ivonne Zavala |
| author_sort | David Andriot |
| collection | DOAJ |
| description | Abstract We explore the possibility that our universe’s current accelerated expansion is explained by a quintessence model with an exponential scalar potential, V = V 0 e −λ ϕ , keeping an eye towards λ ≥ 2 $$ \sqrt{2} $$ and an open universe, favorable to a string theory realisation and with no cosmological horizon. We work out the full cosmology of the model, including matter, radiation, and optionally negative spatial curvature, for all λ > 0, performing an extensive analysis of the dynamical system and its phase space. The minimal physical requirements of a past epoch of radiation domination and an accelerated expansion today lead to an upper bound λ ≲ 3 $$ \sqrt{3} $$ , which is driven slightly up in the presence of observationally allowed spatial curvature. Cosmological solutions start universally in a kination epoch, go through radiation and matter dominated phases and enter an epoch of acceleration, which is only transient for λ > 2 $$ \sqrt{2} $$ . Field distances traversed between BBN and today are sub-Planckian. We discuss possible string theory origins and phenomenological challenges, such as time variation of fundamental constants. We provide theoretical predictions for the model parameters to be fitted to data, most notably the varying dark energy equation of state parameter, in light of recent results from DES-Y5 and DESI. |
| format | Article |
| id | doaj-art-4120f24f20a44f7a8277483751d581e2 |
| institution | Kabale University |
| issn | 1029-8479 |
| language | English |
| publishDate | 2024-08-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-4120f24f20a44f7a8277483751d581e22024-11-24T12:06:47ZengSpringerOpenJournal of High Energy Physics1029-84792024-08-012024816010.1007/JHEP08(2024)117Exponential quintessence: curved, steep and stringy?David Andriot0Susha Parameswaran1Dimitrios Tsimpis2Timm Wrase3Ivonne Zavala4Laboratoire d’Annecy-le-Vieux de Physique Théorique (LAPTh), CNRS, Université Savoie Mont Blanc (USMB), UMR 5108Department of Mathematical Sciences, University of LiverpoolInstitut de Physique des Deux Infinis de Lyon (iP2i), Université de Lyon, UCBL, CNRS/IN2P3, UMR 5822Department of Physics, Lehigh UniversityPhysics Department, Swansea UniversityAbstract We explore the possibility that our universe’s current accelerated expansion is explained by a quintessence model with an exponential scalar potential, V = V 0 e −λ ϕ , keeping an eye towards λ ≥ 2 $$ \sqrt{2} $$ and an open universe, favorable to a string theory realisation and with no cosmological horizon. We work out the full cosmology of the model, including matter, radiation, and optionally negative spatial curvature, for all λ > 0, performing an extensive analysis of the dynamical system and its phase space. The minimal physical requirements of a past epoch of radiation domination and an accelerated expansion today lead to an upper bound λ ≲ 3 $$ \sqrt{3} $$ , which is driven slightly up in the presence of observationally allowed spatial curvature. Cosmological solutions start universally in a kination epoch, go through radiation and matter dominated phases and enter an epoch of acceleration, which is only transient for λ > 2 $$ \sqrt{2} $$ . Field distances traversed between BBN and today are sub-Planckian. We discuss possible string theory origins and phenomenological challenges, such as time variation of fundamental constants. We provide theoretical predictions for the model parameters to be fitted to data, most notably the varying dark energy equation of state parameter, in light of recent results from DES-Y5 and DESI.https://doi.org/10.1007/JHEP08(2024)117Cosmological modelsCosmology of Theories BSMString and Brane Phenomenology |
| spellingShingle | David Andriot Susha Parameswaran Dimitrios Tsimpis Timm Wrase Ivonne Zavala Exponential quintessence: curved, steep and stringy? Journal of High Energy Physics Cosmological models Cosmology of Theories BSM String and Brane Phenomenology |
| title | Exponential quintessence: curved, steep and stringy? |
| title_full | Exponential quintessence: curved, steep and stringy? |
| title_fullStr | Exponential quintessence: curved, steep and stringy? |
| title_full_unstemmed | Exponential quintessence: curved, steep and stringy? |
| title_short | Exponential quintessence: curved, steep and stringy? |
| title_sort | exponential quintessence curved steep and stringy |
| topic | Cosmological models Cosmology of Theories BSM String and Brane Phenomenology |
| url | https://doi.org/10.1007/JHEP08(2024)117 |
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