相关论文: D-term Inflation in Type I String Theory
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…
The simple chaotic inflation is highly consistent with the BICEP2 experiment, and no-scale supergravity can be realized naturally in various string compactifications. Thus, we construct a chaotic inflation model in no-scale supergravity…
The three-year data from WMAP are in stunning agreement with the simplest possible quadratic potential for chaotic inflation, as well as with new or symmetry-breaking inflation. We investigate the possibilities for incorporating these…
Supersymmetry breaking close to the scale of grand unification can explain cosmic inflation. As we demonstrate in this paper, this can be achieved in strongly coupled supersymmetric gauge theories, such that the energy scales of inflation…
We show that a particular class of effective low energy supergravity theories motivated by string theory can provide a promising framework for models of hybrid inflation in which the potential energy which drives inflation originates from…
The first part of this thesis is a general introduction to the bosonic and fermionic string theory, to the concept of D brane and to string dualities. A discussion of anomalies cancellation closes the chapter. The second part of the thesis…
We motivate the study of chiral cosmic strings through a scenario of structure formation which mixes D-term inflation and strings. We then discuss some properties of chiral cosmic strings, and results regarding their evolution and possible…
Inflationary models in string theory which identify the inflaton with an open string modulus lead to effective field theories with non-canonical kinetic terms: Dirac-Born-Infeld scalar field theories. In the case of a $D$-brane moving in an…
"Brane supersymmetry breaking" occurs in String Theory when the only available combinations of D-branes and orientifolds are not mutually BPS and yet do not introduce tree-level tachyon instabilities. It is characterized by the emergence of…
We develop sequestered inflation models, where inflation occurs along flat directions in supergravity models derived from type IIB string theory. It is compactified on a ${\mathbb{T}^6 \over \mathbb{Z}_2 \times \mathbb{Z}_2}$ orientifold…
Anomalous U(1) gauge symmetries can appear both in heterotic and type I string theories. In the heterotic case we find a single anomalous U(1), while in open string theories several such symmetries can appear. Nonetheless, there is a…
Recently, a class of inflation models in supergravity with gauge non-singlet matter fields as the inflaton has been proposed. It is based on a `tribrid' structure in the superpotential and on a Heisenberg symmetry for solving the…
A systematic analysis of possibilities for realizing single-field F-term axion monodromy inflation via the flux-induced superpotential in type IIB string theory is performed. In this well-defined setting the conditions arising from moduli…
Inflation is well known to be difficult in the context of supergravity, if the potential is dominated by the $F$ term. Non-renormalizable terms generically give $|V''|\sim V/M^2$, where $V(\phi)$ is the inflaton potential and $M$ is the…
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…
We propose a class of inflation models in which the coefficient of the inflaton kinetic term rapidly changes with energy scale. This may occur especially if the inflaton moves over a long distance during inflation as in the case of…
In the presence of fields without superpotential but with large vevs through D-terms the mass-squared of the inflaton in the context of supergravity hybrid inflation receives positive contributions which could cancel the possibly negative…
F-term hybrid inflation models in the context of supergravity generically have corrections to the inflaton mass squared of the order of H^{2} (the \eta-problem). In addition they have a problem with large deviations of the spectrum of…
We consider D-term inflation for small couplings of the inflaton to matter fields. Standard hybrid inflation then ends at a critical value of the inflaton field that exceeds the Planck mass. During the subsequent waterfall transition the…
The theory of inflation will be investigated as well as supersymmetry breaking in the context of supergravity, incorporating the target-space duality and the nonperturbative gaugino condensation in the hidden sector. We found an…