Related papers: Defect Formation with Bulk Fields

In this work we investigate the effect of a kind of scalar field, called chameleon, on the evolution of universe. We put this scalar field in the bulk. It is displayed that this scalar field gives us an exponential expansion in early time…

We investigate quantum field theory in a bulk space with boundary, which represents a 3-brane. Both flat and anti-de Sitter backgrounds are considered. The basic idea is to keep local commutativity only on the brane, giving up this…

The motivation for studying the rolling tachyon and non-commutative inflation comes from string theory. In the tachyon inflation scenario, metric perturbations are created by tachyon field fluctuations during inflation. We drive the exact…

We consider the evolution of a bulk scalar field in anti-de Sitter (AdS) spacetime linearly coupled to a scalar field on a de Sitter boundary brane. We present results of a spectral analysis of the system, and find that the model can…

We study cosmological defect formation after brane inflation. The cosmological defects are corresponding to the branes that have less than three spacial dimensions in the uncompactified spacetime. Contrary to the previous arguments,…

We demonstrate the attractor behavior of inflation driven by a scalar field or a tachyon field in the context of recently proposed four-dimensional effective gravity induced on the world-volume of a three-brane in five-dimensional Einstein…

We argue that an extension of the Minimal Supersymmetric Standard Model that gives rise to viable thermal inflation, and so does not suffer from a Polonyi/moduli problem, should contain right-handed neutrinos which acquire their masses due…

String theory gives rise to various mechanisms to generate primordial inflation, of which ``brane inflation'' is one of the most widely considered. In this scenario, inflation takes place while two branes are approaching each other, and the…

We present a detailed systematics for comparing warped brane inflation with the observations, incorporating the effects of both moduli stabilization and ultraviolet bulk physics. We explicitly construct an example of the inflaton potential…

We present a novel scenario for baryogenesis in a hybrid inflation model at the electroweak scale, in which the Standard Model Higgs field triggers the end of inflation. One of the conditions for successful baryogenesis, the departure from…

We analyze warm tachyonic inflation, proposed in the literature, but from the viewpoint of four dimensional effective action for tachyon field on a non-BPS D3-brane. We find that consistency with observational data on density perturbation…

We study the instability of a scalar field at the end of hybrid inflation, using both analytical techniques and numerical simulations. We improve previous studies by taking the inflaton field fully into account, and show that the range of…

Using the boundary state formalism we investigate the effect of tachyon condensation process on a rotating and moving D$p$-brane with various background fields in the bosonic string theory. The rotation and motion are inside the brane…

We consider tachyon effective theory with Born-Infeld electromagnetic fields and investigate the configurational entropy of the various tachyon kink solutions. We find that the configurational entropy stats at a minimum value and saturates…

We consider real and complex scalar fields non-minimally coupled to gravity in the bulk spacetime and study their impact on the brane upon acquiring a non-vanishing vacuum expectation value. When examining the case of the complex scalar…

We describe a general scenario where primordial non-Gaussian curvature perturbations are generated in models with extra scalar fields. The extra scalars communicate to the inflaton sector mainly through the tachyonic (waterfall) field…

We study whether the tachyon mode exists as a physical fluctuation on the 2-brane solution and on the tachyon vacuum solution in cubic open string field theory. Our analysis is based on the Batalin-Vilkovisky formalism. We first construct a…

It is tempting to inflate along one of the many flat directions that arise in supersymmetric theories. The required flatness of the potential to obtain sufficient inflation and to not overproduce density fluctuations occurs naturally.…

Previous studies demonstrate that the inflaton, when coupled to the hypercharge Chern-Simons density, can source an explosive production of helical hypermagnetic fields. Then, in the absence of fermion production, those fields have the…

In a recent paper we showed how Starobinsky-like inflation could emerge from dilaton dynamics in brane cosmology scenarios based on string theory, in which our universe is represented as a three-brane and the effective potential acquires a…