Detecting the dark sector through scalar-induced gravitational waves
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arXiv
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| Auteurs principaux: | , , , |
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866916502048866304 |
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| author | Sui, Xiao-Bin Liu, Jing Yang, Xing-Yu Cai, Rong-Gen |
| author_facet | Sui, Xiao-Bin Liu, Jing Yang, Xing-Yu Cai, Rong-Gen |
| contents | We investigate the evolution of cosmological scalar perturbations in the case that the background radiation is weakly coupled to a light scalar field $ϕ$. The light scalar $ϕ$ is a homogeneous background field with a large initial value. In the radiation-dominated Universe, the coupling term introduces an effective mass to $ϕ$ and the background ultra-relativistic particles. The oscillations of $ϕ$ result in the periodic change of the equation of state parameter and the sound speed, which provides a novel mechanism to amplify subhorizon scalar perturbations through parametric resonance. The amplification of scalar perturbations leads to a stochastic gravitational-waves background~(SGWB) expected to be observed by multiband gravitational wave observers. The observation of the SGWB helps to determine the initial value of $ϕ$ and the coupling strength of the interaction. This mechanism is generally applicable to the interactions that introduce an effective mass, and we take the interaction between $ϕ$ and electrons as a concrete example to illustrate the result. We find that under the condition that the coupling coefficient $λ=10^{-16}$ and the initial value $ϕ_i=10^{18}$ GeV, the resulting SGWB spectrum is expected to be observed by the future observers including LISA, $Taiji$, DECIGO and BBO. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_04220 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Detecting the dark sector through scalar-induced gravitational waves Sui, Xiao-Bin Liu, Jing Yang, Xing-Yu Cai, Rong-Gen Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology We investigate the evolution of cosmological scalar perturbations in the case that the background radiation is weakly coupled to a light scalar field $ϕ$. The light scalar $ϕ$ is a homogeneous background field with a large initial value. In the radiation-dominated Universe, the coupling term introduces an effective mass to $ϕ$ and the background ultra-relativistic particles. The oscillations of $ϕ$ result in the periodic change of the equation of state parameter and the sound speed, which provides a novel mechanism to amplify subhorizon scalar perturbations through parametric resonance. The amplification of scalar perturbations leads to a stochastic gravitational-waves background~(SGWB) expected to be observed by multiband gravitational wave observers. The observation of the SGWB helps to determine the initial value of $ϕ$ and the coupling strength of the interaction. This mechanism is generally applicable to the interactions that introduce an effective mass, and we take the interaction between $ϕ$ and electrons as a concrete example to illustrate the result. We find that under the condition that the coupling coefficient $λ=10^{-16}$ and the initial value $ϕ_i=10^{18}$ GeV, the resulting SGWB spectrum is expected to be observed by the future observers including LISA, $Taiji$, DECIGO and BBO. |
| title | Detecting the dark sector through scalar-induced gravitational waves |
| topic | Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2407.04220 |