Journal article 282 views 76 downloads
Dark energy, D-branes and pulsar timing arrays
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Ivonne Zavala Carrasco
Journal of Cosmology and Astroparticle Physics, Volume: 2023, Issue: 11, Start page: 090
Swansea University Authors:
Debika Chowdhury, Gianmassimo Tasinato , Ivonne Zavala Carrasco
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© 2023 The Author(s). Published by IOP Publishing Ltd on behalf of Sissa Medialab. Distributed under the terms of a Creative Commons Attribution 4.0 International License (CC BY 4.0).
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DOI (Published version): 10.1088/1475-7516/2023/11/090
Abstract
Several pulsar timing array (PTA) collaborations recently announced the first detection of a stochastic gravitational wave (GW) background, leaving open the question of its source. We explore the possibility that it originates from cosmic inflation, a guaranteed source of primordial GW. The inflatio...
| Published in: | Journal of Cosmology and Astroparticle Physics |
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| ISSN: | 1475-7516 |
| Published: |
IOP Publishing
2023
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa65120 |
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| Abstract: |
Several pulsar timing array (PTA) collaborations recently announced the first detection of a stochastic gravitational wave (GW) background, leaving open the question of its source. We explore the possibility that it originates from cosmic inflation, a guaranteed source of primordial GW. The inflationary GW background amplitude is enhanced at PTA scales by a non-standard early cosmological evolution, driven by Dirac-Born-Infeld (DBI) scalar dynamics motivated by string theory. The resulting GW energy density has a broken power-law frequency profile, entering the PTA band with a peak amplitude consistent with the recent GW detection. After this initial DBI kination epoch, the dynamics starts a new phase mainly controlled by the scalar potential. It provides a realization of an early dark energy scenario aimed at relaxing the H0 tension, and a late dark energy model which explains the current cosmological acceleration with no need of a cosmological constant. Hence our mechanism — besides providing a possible explanation for the recent PTA results — connects them with testable properties of the physics of the dark universe. |
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| Keywords: |
Dark energy theory, gravitational waves / theory, Gravitational waves in GRand beyond: theory , physics of the early universe |
| College: |
Faculty of Science and Engineering |
| Funders: |
The authors are partially funded by the STFC grant ST/T000813/1. |
| Issue: |
11 |
| Start Page: |
090 |