Related papers: Braneworld effective action and origin of inflatio…
We investigate the dynamics of a bulk scalar field with various decay channels in the Randall-Sundrum infinite braneworld scenario. A bulk scalar field in this scenario has a quasi-localized mode which dominates the late-time behavior near…
The low energy effective theory for the Randall-Sundrum two-brane system is investigated with an emphasis on the role of the non-linear radion in the brane world. It is shown that the gravity on the brane world is described by a…
In this thesis, we explore three phenomenological alternatives to the current paradigm of the standard inflationary big bang scenario. The three alternative themes are spin torsion (or Einstein-Cartan-Kibble-Sciama) theories, extra…
We discuss sneutrino inflation in the brane-world scenario. We work in the Randall-Sundrum type II brane-world, generalized with the introduction of the Gauss-Bonnet term, a correction to the effective action in string theories. We find…
We study inflation arising from the motion of a BPS D3-brane in the background of a stack of k parallel D5-branes. There are two scalar fields in this set up-- (i) the radion field R, a real scalar field, and (ii) a complex tachyonic scalar…
Much work has been devoted to the phenomenology and cosmology of the so-called braneworld universe, where our (3+1)-dimensional universe lies on a brane surrounded by a (4+1)-dimensional bulk spacetime that is essentially empty except for a…
It has very recently been realized that coupling branes to higher dimensional quantum gravity theories and considering the consistency of what lives on the branes, one is able to understand whether such theories can belong either to the…
Cosmic inflation driven by branes wrapping the extra dimensions involves Kaluza-Klein (KK) degrees of freedom in addition to the zero-mode position of the brane which plays the role of the inflaton. As the wrapped brane passes by localized…
We analyse the mechanism of quintessential inflation in brane world scenarios for a number of particle physics inspired scalar potentials. We constrain the parameter space of those scalar potentials and comment on the likelihood that we…
We discuss various realizations of the four dimensional braneworld inflation in warped geometries of string theory. In all models the inflaton field is represented by a Dp probe brane scalar specifying its position in the warped throat of…
Following our previous work in noncommutative braneworld inflation (arXiv:0911.4418), in this paper we use the smeared, coherent state picture of noncommutativity to study evolution of perturbations in a noncommutative braneworld scenario.…
The physics during the inflationary stage of the universe is of quantum nature involving extremely high energy densities. Moreover, it is out of equilibrium on a fastly expanding dynamical geometry.We present in these lectures…
Positively-curved, oscillatory universes have recently been shown to have important consequences for the pre-inflationary dynamics of the early universe. In particular, they may allow a self-interacting scalar field to climb up its…
Low-energy effective theories provide a natural description of four-dimensional physics in higher-dimensional geometries, where the imprint of the bulk geometry appears as parameters of the lower-dimensional theory. Inspired by the…
The stability of the modular field in a warped brane world scenario has been a subject of interest for a long time. Goldberger \& Wise ( GW ) proposed a mechanism to achieve this by invoking a massive scalar field in the bulk space-time…
It has been shown in the last few years that 3-form fields present viable cosmological solutions for inflation and dark energy with particular observable signatures distinct from those of canonical single scalar field inflation. The aim of…
We derive two classes of brane-world solutions arising in the presence of a bulk scalar field. For static field configurations, we adopt a time-dependent, factorizable metric ansatz that allows for radion stabilization. The solutions are…
We consider the evolution of cosmological perturbations during radion stabilization, which we assume to happen after a period of inflation in the early universe. Concentrating on the Randall-Sundrum brane world scenario, we find that if…
In this article we study a constant-roll inflationary model in the context of brane-world cosmology caused by a quintessence scalar field for warm inflation with a constant dissipative parameter Q =$\Gamma$/3H. We determine the analytical…
In brane world scenarios with a bulk scalar field between two branes it is known that 4-dimensional Einstein gravity is restored at low energies on either brane. By using a gauge-invariant gravitational and scalar perturbation formalism we…