Non-minimal coupling in light of ACT
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arXiv
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| Hauptverfasser: | , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866909819575730176 |
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| author | Gao, Qing Gong, Yungui Yi, Zhu Zhang, Fengge |
| author_facet | Gao, Qing Gong, Yungui Yi, Zhu Zhang, Fengge |
| contents | The latest ACT data release disfavors the attractor $n_s=1-2/N$. In inflationary models with nonminimal coupling, such attractors typically arise in the strong coupling limit. To align with observational constraints, we focus on nonminimal coupling models with small coupling constants. For the model with the coupling function $Ω(ϕ) = 1 + ξf(ϕ)$ and the potential $V(ϕ) = λ^2 f^2(ϕ)$, we find that observational data constrain the parameters as $0.1 \lesssim ξ\lesssim 35$ and $0 \lesssim k \lesssim 1.5$ for $f(ϕ) = ϕ^k$ at the $1σ$ confidence level. With the help of the nonmiminal coupling $Ω(ϕ) = 1 + ξϕ^2$, the hilltop inflation and power-law inflation models with power indices $2/3$ and $1/3$ can be consistent with observational data within the $1σ$ range. We also give the viable parameter regions for $ξ$ for these three models. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_15218 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Non-minimal coupling in light of ACT Gao, Qing Gong, Yungui Yi, Zhu Zhang, Fengge Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Theory The latest ACT data release disfavors the attractor $n_s=1-2/N$. In inflationary models with nonminimal coupling, such attractors typically arise in the strong coupling limit. To align with observational constraints, we focus on nonminimal coupling models with small coupling constants. For the model with the coupling function $Ω(ϕ) = 1 + ξf(ϕ)$ and the potential $V(ϕ) = λ^2 f^2(ϕ)$, we find that observational data constrain the parameters as $0.1 \lesssim ξ\lesssim 35$ and $0 \lesssim k \lesssim 1.5$ for $f(ϕ) = ϕ^k$ at the $1σ$ confidence level. With the help of the nonmiminal coupling $Ω(ϕ) = 1 + ξϕ^2$, the hilltop inflation and power-law inflation models with power indices $2/3$ and $1/3$ can be consistent with observational data within the $1σ$ range. We also give the viable parameter regions for $ξ$ for these three models. |
| title | Non-minimal coupling in light of ACT |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2504.15218 |