Related papers: Recent developments in string model-building and c…
We study the spectrum, couplings and cosmological and astrophysical implications of the moduli fields for the class of Calabi-Yau IIB string compactifications for which moduli stabilisation leads to an exponentially large volume V ~ 10^{15}…
We examine how reheating occurs after brane-antibrane inflation in warped geometries, such as those which have recently been considered for Type IIB string vacua. We adopt the standard picture that the energy released by brane annihilation…
We consider cosmological scenarios in which density perturbations are generated by the quantum fluctuations of the inflaton field at early times; the late time dynamics involves a modulus which first dominates the energy density of the…
We consider the cosmological evolution induced by the free energy F of a gas of maximally supersymmetric heterotic strings at finite temperature and weak coupling in dimension D>=4. We show that F, which plays the role of an effective…
A generic feature of inflationary models in supergravity/string constructions is vacuum misalignment for the moduli fields. The associated production of moduli particles leads to an epoch in the post-inflationary history in which the energy…
We discuss the physics of moduli (light scalar fields with Planck-suppressed couplings to matter) in the case of low-scale supersymmetry breaking such as gauge mediation. We argue that even if the mechanism of moduli stabilization is…
One possibility for identifying the inflaton in the framework of string theory is that it is a $D$-brane modulus. This option involves a specific, non-canonical form of the kinetic energy -- the Dirac-Born-Infeld action. This note…
We show that a moduli space of the form predicted by string theory, lifted by supersymmetry breaking, gives rise to successful inflation for large regions of parameter space without any modification or fine tuning. This natural realization…
The latest Planck results show a power deficit in the temperature anisotropies near $\ell \approx 20$ in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary…
We present a viable string embedding of Affleck-Dine baryogenesis in type IIB sequestered models where the late-time decay of the lightest modulus reheats the universe to relatively low temperatures. We show that if inflation is driven by a…
Standard results in 4d N=1 string compactifications assign a number of moduli to each space-time filling D-brane, computed by analysing the D-brane action in a fixed background. We revisit such conventional wisdom and argue that this naive…
Among the inflationary models based on string theory, the D3/D7 model has the advantage that the flatness of the inflaton potential can be protected even with moduli stabilization. However, the Abrikosov-Nielsen-Olesen BPS cosmic strings…
In this talk I will discuss the role of finite temperature quantum corrections in string cosmology and show that they can lead to a stabilization mechanism for the volume moduli. I will show that from the higher dimensional perspective this…
We present a study of open inflation cosmological scenarios in which cosmic strings form betwen the two inflationary epochs. It is shown that in these models strings are stretched outside the horizon due to the inflationary expansion but…
In the framework of Supersymmetric Grand Unified Theories (SUSY GUTs), the universe undergoes a cascade of symmetry breakings, during which topological defects can be formed. We address the question of the probability of cosmic string…
Brane inflation is a specific realization of the inflationary universe scenario in the early universe within the brane world framework in string theory. The naturalness and robustness of this realistic scenario is explained. Its predictions…
We study the cosmological properties of a metastable de Sitter vacuum obtained recently in the framework of type IIB flux compactifications in the presence of three D7-brane stacks, based on perturbative quantum corrections at both…
The recent discovery of B-mode polarizations in the CMB by the BICEP2 collaboration motivates the study of large-field inflation models which can naturally lead to significant tensor-to-scalar ratios. A class of such models in string theory…
The "central" region of moduli space of M- and string theories is where the string coupling is about unity and the volume of compact dimensions is about the string volume. Here we argue that in this region the non-perturbative potential…
A survey of solutions to the cosmological moduli problem in string theory. The only extant proposal which may work is Intermediate Scale Inflation as proposed by Randall and Thomas. Supersymmetry preserving dynamics which could give large…