Large nonlocal non-Gaussianity from a curvaton brane

Abstract

We use a generalized N formalism to study the generation of the primordial curvature perturbation in the curvaton brane scenario inspired by stringy compactifications. We note that the non-Gaussian features, especially the trispectra, crucially depend on the decay mechanism in a general curvaton scenario. Specifically, we study the bispectra and trispectra of the curvaton brane model in detail to illustrate the importance of curvaton decay in generating nonlinear fluctuations. When the curvaton brane moves nonrelativistically during inflation, the shape of non-Gaussianity is local, but the corresponding size is different from that in the standard curvaton scenario. When the curvaton brane moves relativistically in inflationary stage, the shape of non-Gaussianity is of equilateral type.

Higgs Boson in Rg Running Inflationary Cosmology

“…Instead of a matter-like curvaton oscillation with w = 0 as studied in [40,46], a λh 4 potential yields an effective equation of state for the Higgs boson, which is the same as radiation with w h = 1 3 [47,48]. Thus, this generalized curvaton mechanism [49] may be used to generate the primordial curvature perturbation in agreement with the current CMB measurements.…”

Primordial black holes from sound speed resonance in the inflaton-curvaton mixed scenario

“…The calculation could be performed on other hypersurfaces, e.g. a uniform curvaton density hypersurface [85]. Thus, on this uniform-total density hypersurface, we have…”

Inflation, Cosmic Perturbations and Non-Gaussianities

“…Finally, we need to fix the ambiguity of decomposition in Eq. (114). For this purpose, it is convenient to choose the two polarization tensors as the spin 2 eigenfunctions of rotation along the k-axis:…”

“…Here we assume curvaton decays on uniform total energy density slice. Otherwise, there is additional slice matching[114].…”