Primordial Curvature Fluctuation and Its Non-Gaussianity in Models with Modulated Reheating
| dc.creator | Ichikawa, Kazuhide | |
| dc.creator | Suyama, Teruaki | |
| dc.creator | Takahashi, Tomo | |
| dc.creator | Yamaguchi, Masahide | |
| dc.date | 2008-07-25 | |
| dc.date.accessioned | 2026-07-07T11:45:04Z | |
| dc.date.available | 2026-07-07T11:45:04Z | |
| dc.description | We investigate non-Gaussianity in the modulated reheating scenario where fluctuations of the decay rate of the inflaton generate adiabatic perturbations, paying particular attention to the non-linearity parameters $f_{\rm NL}, τ_{\rm NL}$ and $g_{\rm NL}$ as well as the scalar spectral index and tensor-to-scalar ratio which characterize the nature of the primordial power spectrum. We also take into account the pre-existing adiabatic perturbations produced from the inflaton fluctuations. It has been known that the non-linearity between the curvature perturbations and the fluctuations of the decay rate can yield non-Gaussianity at the level of $f_{\rm NL} \sim \mathcal{O}(1)$, but we find that the non-linearity between the decay rate and the modulus field which determines the decay rate can generate much greater non-Gaussianity. We also discuss a consistency relation among non-linearity parameters which holds in the scenario and find that the modulated reheating yields a different one from that of the curvaton model. In particular, they both can yield a large positive $f_{\rm NL}$ but with a different sign of $g_{\rm NL}$. This provides a possibility to discriminate these two competitive models by looking at the sign of $g_{\rm NL}$. Furthermore, we work on some concrete inflation models and investigate in what cases models predict the spectral index and the tensor-to-scalar ratio allowed by the current data while generating large non-Gaussianity, which may have many implications for model-buildings of the inflationary universe. | |
| dc.description | 38 pages, 12 figures | |
| dc.identifier | https://arxiv.org/abs/0807.3988 | |
| dc.identifier | http://arxiv.org/abs/0807.3988 | |
| dc.identifier | Phys.Rev.D78:063545,2008 | |
| dc.identifier | doi:10.1103/PhysRevD.78.063545 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/201768 | |
| dc.subject | Astrophysics | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.subject | High Energy Physics - Theory | |
| dc.title | Primordial Curvature Fluctuation and Its Non-Gaussianity in Models with Modulated Reheating | |
| dc.type | text |