Assessing cosmological evidence for non-minimal coupling
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| author | Wolf, William J. García-García, Carlos Anton, Theodore Ferreira, Pedro G. |
| author_facet | Wolf, William J. García-García, Carlos Anton, Theodore Ferreira, Pedro G. |
| contents | The recent observational evidence of deviations from the $Λ$-Cold Dark Matter ($Λ$CDM) model points towards the presence of evolving dark energy. The simplest possibility consists of a cosmological scalar field $φ$, dubbed quintessence, driving the accelerated expansion. We assess the evidence for the existence of such a scalar field. We find that, if the accelerated expansion is driven by quintessence, the data favour a potential energy $V(φ)$ that is concave, i.e., $m^2=d^2V/dφ^2<0$. Furthermore, and more significantly, the data strongly favour a scalar field that is non-minimally coupled to gravity (Bayes factor $\log(B) = 7.34 \pm 0.6$), leading to time variations in the gravitational constant on cosmological scales, and the existence of fifth forces on smaller scales. The fact that we do not observe such fifth forces implies that either new physics must come into play on non-cosmological scales or that quintessence is an unlikely explanation for the observed cosmic acceleration. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_07679 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Assessing cosmological evidence for non-minimal coupling Wolf, William J. García-García, Carlos Anton, Theodore Ferreira, Pedro G. Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory The recent observational evidence of deviations from the $Λ$-Cold Dark Matter ($Λ$CDM) model points towards the presence of evolving dark energy. The simplest possibility consists of a cosmological scalar field $φ$, dubbed quintessence, driving the accelerated expansion. We assess the evidence for the existence of such a scalar field. We find that, if the accelerated expansion is driven by quintessence, the data favour a potential energy $V(φ)$ that is concave, i.e., $m^2=d^2V/dφ^2<0$. Furthermore, and more significantly, the data strongly favour a scalar field that is non-minimally coupled to gravity (Bayes factor $\log(B) = 7.34 \pm 0.6$), leading to time variations in the gravitational constant on cosmological scales, and the existence of fifth forces on smaller scales. The fact that we do not observe such fifth forces implies that either new physics must come into play on non-cosmological scales or that quintessence is an unlikely explanation for the observed cosmic acceleration. |
| title | Assessing cosmological evidence for non-minimal coupling |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2504.07679 |