Non-Gaussianity from massless preheating
نویسندگان
چکیده
Preheating can convert superhorizon fluctuations of light scalar fields present at the end of inflation into observable density perturbations. We show in detail how lattice field theory simulations and the separate universes approximation can be used to calculate these perturbations and make predictions for the nonlinearity parameter fNL. We also present a simple approximation scheme that can reproduce these results analytically. Applying these methods to the massless preheating model, we determine the parameter values that are ruled out by too high levels of nonGaussianity. PACS numbers: 98.80.Cq, 11.15.Kc
منابع مشابه
Non-Gaussianity from Instant and Tachyonic Preheating
We study non-Gaussianity in two distinct models of preheating: instant and tachyonic. In instant preheating non-Gaussianity is sourced by the local terms generated through the coupled perturbations of the two scalar fields. We find that the non-Gaussianity parameter is given by f NL ∼ 2g < O(1), where g is a coupling constant, so that instant preheating is unlikely to be constrained by WMAP or ...
متن کاملVery Large Primordial Non-Gaussianity from multi-field: Application to Massless Preheating
In this paper we derive a generic expression, which is valid for scales larger than Hubble radius and contains only the local terms, for the second order curvature perturbations for more than one field, provided the expansion is sourced by the energy density of a single field. As an application, motivated by our previous paper [1], we apply our formalism to two fields during preheating, where t...
متن کاملNon-Gaussianity from preheating.
We consider a two-field model for inflation where the second order metric perturbations can be amplified by a parametric resonance during preheating. We demonstrate that there can arise a considerable enhancement of non-Gaussianity sourced by the local terms generated through the coupled perturbations. We argue that the non-Gaussianity parameter could be as large as f(NL) approximately 50. Our ...
متن کاملStatistics of Sunyaev-Zel’dovich Cluster Surveys
We describe a detailed analytic model for predicting statistical quantities (such as number counts, redshift distributions and sizes) of clusters detected in blank-field, thermal Sunyaev-Zel’dovich effect experiments. We include in this model the possibility of non-Gaussian density perturbations in the early Universe and also describe a simple model for the effects of preheating on cluster Suny...
متن کاملPreheating in an expanding universe: Analytic results for the massless case
Analytic results are presented for preheating in both flat and open models of chaotic inflation, for the case of massless inflaton decay into further inflaton quanta. It is demonstrated that preheating in both these cases closely resembles that in Minkowski spacetime. Furthermore, quantitative differences between preheating in spatially flat and open models of inflation remain of order 10 for t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008