相关论文: String Theory and Hybrid Inflation/Acceleration
In this work, we construct an explicit string motivated example of three-field inflation in a related, yet distinct from, the recently discovered perturbative large volume scenario (pLVS). Contrary to the usual constructions, in this set…
The scale at which supersymmetry is broken and the mechanism by which supersymmetry breaking is fed down to the observable sector has rich implications on the way Nature may have chosen to accomplish inflation. We discuss a simple model for…
We construct two simple effective field theory versions of {\it Hybrid Natural Inflation (HNI)} that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, $V=\Delta^4(1+a\cos(\phi/f))$,…
We investigate the possibility of preheating in hybrid inflation. This scenario involves at least two scalar fields, the inflaton field $\phi$, and the symmetry breaking field $\sigma$. We found that the behavior of these fields after…
Inflation is now a basic ingredient of the modern cosmology. After reviewing the basic characteristics of inflation, we briefly discuss inflation in string and brane theories, focusing on the problem of the exit from inflation in these…
We show that the naive application of the Kibble mechanism seriously underestimates the initial density of cosmic superstrings that can be formed during the annihilation of D-branes in the early universe, as in models of brane-antibrane…
We review the recent developments in obtaining accelerating cosmologies and/or inflation from higher-dimensional gravitational theories, in particular superstring theories in ten dimensions and M-theory in eleven dimensions. We first…
We analyze the slow-roll inflation mechanism in brane framework with a real Higgs field confined on the brane. We prove that inflation occur for field value below the 4-dimensional Planck scale and produce cosmological perturbations in…
Brane inflation in superstring theory predicts that cosmic strings (but not domain walls or monopoles) are produced towards the end of the inflationary epoch. Here, we discuss the production, the spectrum and the evolution of such cosmic…
Motivated by the string landscape we examine scenarios for which inflation is a two-step process, with a comparatively short inflationary epoch near the string scale and a longer period at a much lower energy (like the TeV scale). We…
Within the context of SUSY GUTs, cosmic strings are generically formed at the end of hybrid inflation. However, the WMAP CMB measurements strongly constrain the possible cosmic strings contribution to the angular power spectrum of…
We construct a hybrid inflationary model associated with the superheavy scale of the minimal supersymmetric standard model which is based on the simplest superpotential for symmetry breaking and in which the inflaton potential along the…
We consider the problem of constructing a non-singular inflationary universe in stringy gravity via branch changing, from a previously superexponentially expanding phase to an FRW-like phase. Our approach is based on the phase space…
The influence of higher-order terms in the K\"{a}hler potential of the supergravity D-term inflation model on the density perturbation is studied. We show that these terms can make the inflaton potential flatter, which lowers the energy…
We point out the existing confusions about the slowroll parameters and conditions for multifield inflation. If one requires the fields to roll down the gradient flow, we find that only articles adopting the Hubble slowroll expansion are on…
Supersymmetry-based hybrid inflation models (referred to as `spontaneously broken supersymmetry' by the Planck collaboration) are attractive for several reasons, including the appealing feature that inflation is associated with local gauge…
The potential during inflation must be very flat in, at least, the direction of the inflaton. In renormalizable global supersymmetry, flat directions are ubiquitous, but they are not preserved in a generic supergravity theory. It is known…
Global topological defects may account for the large cold spot observed in the Cosmic Microwave Background. We explore possibilities of constructing models of supersymmetric F-term hybrid inflation, where the waterfall fields are globally…
We study slow-roll inflation on a three-brane in a five-dimensional bulk where the effects of energy loss from the brane due to graviton emission is included in a self-consistent manner. We explicitly derive the form of the energy loss term…
Inflationary models driven by a large number of axion fields are discussed in the context of type IIB compactifications with N=1 supersymmetry. The inflatons arise as the scalar modes of the R-R two-forms evaluated on vanishing two-cycles…