ﻻ يوجد ملخص باللغة العربية
We study the preheating process in a model of DBI inflation with a DBI-type inflaton coupling to a canonical entropy field. At the end of inflation, the inflaton field oscillates around its vacuum which can arise from an infrared cutoff parameter on the warp factor and correspondingly the evolution of its fluctuations can be approximately described by a generalized Hills equation in third order. We study the field fluctuations numerically and show that they could grow exponentially since the instability bands commonly exist in the DBI models if the amplitudes of background oscillations are of order or larger than the cutoff parameter. Our numerical result also reveals that the particle excitation of the matter field is more dramatic than that in usual case since the parametric resonance lasts longer when the effect of a warp factor is taken into account. Therefore, we conclude that the preheating process in the model of DBI inflation could be more efficient than that in standard inflation models.
Plateau inflation is an experimentally consistent framework in which the scale of inflation can be kept relatively low. Close to the edge of the plateau, scalar perturbations are subject to a strong tachyonic instability. Tachyonic preheating is real
During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored. We do a fu
We study preheating in the Palatini formalism with a quadratic inflaton potential and an added $alpha R^2$ term. In such models, the oscillating inflaton field repeatedly returns to the plateau of the Einstein frame potential, on which the tachyonic
We analyze and compare the multi-field dynamics during inflation and preheating in symmetric and asymmetric models of $alpha$-attractors, characterized by a hyperbolic field-space manifold. We show that the generalized (asymmetric) E- and (symmetric)
It is possible to couple Dirac-Born-Infeld (DBI) scalars possessing generalized Galilean internal shift symmetries (Galileons) to nonlinear massive gravity in four dimensions, in such a manner that the interactions maintain the Galilean symmetry. Suc