Related papers: Tachyon Field in Intermediate Inflation
The generality of inflation in closed FRW Universe is studied for the models with a scalar field on a brane and with a complex scalar field. The results obtained are compared with the previously known results for the model with a scalar…
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…
In this paper we show that certain types of cosmological brane configurations may induce topological inflation. In generic models for topological inflation, there is a strict bound for the potential of the inflaton field. Naively, it seems…
The recent three-year WMAP data selects large-field models with certain power-law potentials and small-field models for all power-law potentials as consistent inflation models. We study the large-field and small-field inflation model with a…
We study inflation driven by the tachyon field in the holographic braneworld by assuming the second slow-roll parameter $\eta$ is constant. The parameter $\eta$ can be either defined by the tachyon scalar field and the Hubble parameter or…
The BICEP2 observations, if confirmed, point to a high scale of inflation and large field excursions during the inflationary era. Non-compact string moduli spaces are a suggestive setting for these phenomena. While unlikely to be described…
This article provides an introductory review of inflation and cosmological perturbation theory. I begin by motivating the need for an epoch of inflation during the early stages of the radiation dominated era, and describe how inflation is…
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 discuss inflation models within supersymmetry and supergravity frameworks with a landscape of chiral superfields and one $U(1)$ shift symmetry which is broken by non-perturbative symmetry breaking terms in the superpotential. We label…
We propose new classes of inflation models based on the modular symmetry, where the modulus field $\tau$ serves as the inflaton. We establish a connection between modular inflation and modular stabilization, wherein the modulus field rolls…
We propose a model of inflation with a suitable potential for a single scalar field which falls in the wide class of hilltop inflation. We derive the analytical expressions for most of the physical quantities related to inflation and show…
We propose a new scenario for D-term inflation which appears quite straightforwardly in the open string sector of intersecting brane models. We take the inflaton to be a chiral field in a bifundamental representation of the hidden sector…
A warm inflationary Universe in the Randall-Sundrum II model during intermediate inflation is studied. For this purpose, we consider a general form for the dissipative coefficient $\Gamma(T,\phi)=C_{\phi}\,\frac{T^{m}}{\phi^{m-1}}$, and…
We establish for the first time the conditions that must be imposed on the action for a magnetic universe in a theory of non-linear electrodynamics in order to have an asymptotically de Sitter initial state followed by a slow roll…
Inflation models based on scalar-tensor theories of gravity are formulated in the Jordan frame but most often analysed in the Einstein frame. The transformation between the frames is not always desirable. In this work we formulate slow-roll…
We show that in hybrid inflation it is possible to generate large second-order perturbations in the cosmic microwave background due to the instability of the tachyonic field during preheating. We carefully calculate this effect from the…
A warm-intermediate inflationary universe model is studied in the presence of the Galileon coupling $G(\phi,X)=g(\phi)X$. General conditions required for successful inflation are deduced and discussed from the background and cosmological…
Loop quantum cosmology (LQC) predicts a nonsingular evolution of the universe through a bounce in the high energy region. We show that this is always true in tachyon matter LQC. Different from the classical Friedman-Robertson-Walker (FRW)…
We explore some issues in slow roll inflation in situations where field excursions are small compared to $M_p$. We argue that for small field inflation, minimizing fine tuning requires low energy supersymmetry and a tightly constrained…
Inflation may occur while rolling into the metastable supersymmetry-breaking vacuum of massive supersymmetric QCD. We explore the range of parameters in which slow-roll inflation and long-lived metastable supersymmetry breaking may be…