Related papers: On the Initial Conditions for Brane Inflation

Brane inflation and the production of topological defects at the end of the inflationary phase are discussed. After a description of the inflationary setup we discuss the properties of the cosmic strings produced at the end of inflation.…

We construct a string-inspired nonsingular cosmological scenario in which an inflaton field is driven up the potential before the graceful exit by employing a low-energy string effective action with an orbifold compactification. This sets…

We propose a new way of obtaining slow-roll inflation in the context of higher dimensional models motivated by string and M theory. In our model, all extra spatial dimensions are orbifolded. The initial conditions are taken to be a hot…

Higher-form flux that extends in all 3+1 dimensions of spacetime is a source of positive vacuum energy that can drive meta-stable eternal inflation. If the flux also threads compact extra dimensions, the spontaneous nucleation of a bubble…

We propose an alternative inflationary universe scenario in the context of Randall-Sundrum braneworld cosmology. In this new scenario the existence of extra-dimension(s) plays an essential role. First, the brane universe is initially in the…

Brane inflationary universe model in the context of intermediate inflation is studied. General conditions for this model to be realizable are discussed. In the high-energy limit we describe in great details the characteristic of this model.

After a brief summary of general relativity and cosmology, we present the basic concepts underlying inflation, the currently best motivated models for the early Universe. We describe the simplest inflation models, based on a single scalar…

We consider the possibility that the universe, viewed as a three-brane, originated in a region of strong external field strength due to a four-form gauge field in the bulk. It is shown that in a scenario of this kind inflation is generic…

I review some aspects of obtaining inflation from string theory, in particular brane-antibrane inflation within the framework of KKLMMT, and racetrack inflation. Further, I discuss recent work on the problem of reheating after…

We study the cosmological evolution of a D3-brane universe in a type 0 string background. We follow the brane-universe along the radial coordinate of the background and we calculate the energy density which is induced on the brane because…

We propose a stringy version of the old inflation scenario which does not require any slow-roll inflaton potential and is based on a specific example of string compatification with warped metric. Our set-up admits the presence of…

I describe a dynamical mechanism for solving the fine-tuning problem of brane-antibrane inflation. By inflating with stacks of branes and antibranes, the branes can naturally be trapped at a metastable minimum of the potential. As branes…

The initial condition problem of inflation is examined from the perspective of both spacetime embedding and scalar field dynamics. The spacetime embedding problem is solved for arbitrary initial spatial curvature Omega, which generalizes…

In a simple reanalysis of the KKLMMT scenario, we argue that the slow roll condition in the D3-anti-D3-brane inflationary scenario in superstring theory requires no more than a moderate tuning. The cosmic string tension is very sensitive to…

Space-based missions studying the cosmic microwave background (CMB) have progressively refined the parameter space in conventional models of inflation shortly ($\sim 10^{-37}$ seconds) after the big bang. While most inflationary scenarios…

High-scale string inflationary models are in well-known tension with low-energy supersymmetry. A promising solution involves models where the inflaton is the volume of the extra dimensions so that the gravitino mass relaxes from large…

We study the conditions needed to have an early epoch of inflationary expansion with a potential coming from IIB superstring theory with fluxes involving two moduli fields. The phenomenology of this potential is different from the usual…

In String theory realizations of inflation, the end point of inflation is often brane-anti brane annihilation. We consider the processes of reheating of the Standard Model universe after brane inflation. We identify the channels of inflaton…

The possibility of the resilience of the beginning of inflation under unfavorable conditions is examined by considering the initial state of the inflaton field to be in the form of a relativistic gas with some of its properties in close…

As a first step towards inflation in genuinely F-theoretic setups, we propose a scenario where the inflaton is the relative position of two 7-branes on holomorphic 4-cycles. Non-supersymmetric gauge flux induces an attractive inter-brane…