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arXiv · 2310.14606

Anisotropies in Scalar-Induced Gravitational-Wave Background from Inflaton-Curvaton Mixed Scenario with Sound Speed Resonance

Yan-Heng Yu·Sai Wang
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Abstract

We propose a new model to generate large anisotropies in the scalar-induced gravitational wave (SIGW) background via sound speed resonance in the inflaton-curvaton mixed scenario. Cosmological curvature perturbations are not only exponentially amplified at a resonant frequency, but also preserve significant non-Gaussianity of local type described by $f_{\mathrm{nl}}$. Besides a significant enhancement of energy-density fraction spectrum, large anisotropies in SIGWs can be generated, because of super-horizon modulations of the energy density due to existence of primordial non-Gaussianity. A reduced angular power spectrum $\tilde{C}_{\ell}$ could reach an amplitude of $[\ell(\ell+1)\tilde{C}_{\ell}]^{1/2} \sim 10^{-2}$, leading to potential measurements via planned gravitational-wave detectors such as DECIGO. The large anisotropies in SIGWs would serve as a powerful probe of the early universe, shedding new light on the inflationary dynamics, primordial non-Gaussianity, and primordial black hole dark matter.

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Yan-Heng Yu, Sai Wang. 2023-10-23. Anisotropies in Scalar-Induced Gravitational-Wave Background from Inflaton-Curvaton Mixed Scenario with Sound Speed Resonance. https://doi.org/10.1103/physrevd.109.083501

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