Braneworld nonminimal inflation with induced gravity

Abstract

We study cosmological inflation on a warped DGP braneworld where inflaton field is nonminimally coupled to induced gravity on the brane. We present a detailed calculation of the perturbations and inflation parameters both in Jordan and Einstein frame. We analyze the parameters space of the model fully to justify about the viability of the model in confrontation with recent observational data. We compare the results obtained in these two frames also in order to judge which frame gives more acceptable results in comparison with observational data.PACS numbers: 98.80. Cq,

DBI inflation with a nonminimally coupled Gauss-Bonnet term

“…So, in order to obtain scalar and tensorial perturbations in our setup, it is enough to consider the slow-roll approximation at the large scales k ( aH. In this scale, € È, € É, _ È, and _ É are negligible (see [53][54][55][56]). So, at large scales, the perturbed equation of motion takes the following form:…”

Dynamical system approach of non-minimal coupling in holographic cosmology

“…The motivation for including a NMC term arises at the quantum level when quantum corrections to the scalar field theory are considered. This kind of NMC to gravity has been discussed enough in four dimensions [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41], in extra dimensions [42][43][44][45] and also in IG [46]. It turns out that in general relativity, the coupling constant is valued to 1/6 [47].…”

“…This work is also a complementary of the minimally coupled scalar field to the gravity [48] where the authors considered the dynamics of a scalar field in a Dvali-Gabadadze-Porrati brane, of those of [49,50] where the scalar field is trapped in the RSII brane and of the IG of a NMC scalar field [42,43]. Both of above the works used the geometrical approach to derive the effective Einstein equations projected onto the brane.…”

Lowering the self-coupling of the scalar field in the generalized Higgs inflation

“…The nearly scale invariant, adiabatic and Gaussian distribution of the perturbations modes is one of the notable predictions of the simple single field inflation (Maldacena 2003). However, by proposing some extended models of inflation and considering the non-linear perturbations, it is possible to predict some level of non-Gaussianity of the primordial perturbations (Maldacena 2003, Bartolo et al 2004, Babich et al 2004, Seery and Lidsey 2005, Chen 2010, De Felice and Tsujikawa 2011a, De Felice and Tsujikawa 2011b, Nozari and Rashidi 2012, Nozari and Rashidi 2013a, Nozari and Rashidi 2013b, Nozari and Rashidi 2014, Nozari and Rashidi 2016a, Nozari and Rashidi 2016b, Nozari and Rashidi 2017. So, it is reasonable to expect a level non-Gaussianity in future observation.…”