Related papers: Dilaton Production in String Cosmology
We show that it is possible to combine an early phase of String Gas Cosmology which can explain the origin of the observed structures on cosmological scales with a short later period of power law inflation which creates spatial flatness.…
Within the framework of a novel functional method on the world-sheet of the string, we discuss simple but re-summed (in the Regge slope) inflationary scenarios in the context of closed Bosonic strings, living in four target-space…
We study the cosmology of a recent model of supersymmetry breaking, in the presence of a tuneable positive cosmological constant, based on a gauged shift symmetry of a string modulus that can be identified with the string dilaton. The…
We consider the dilaton in the strong string coupling limit and elaborate on the original idea of Damour and Polyakov whereby the dilaton coupling to matter has a minimum with a vanishing value at finite field-value. Combining this type of…
In this work we review the application of a functional method, serving as an alternative to the Wilsonian Exact Renormalization approach, to stringy bosonic $\sigma$-models with metric and dilaton backgrounds on a spherical world sheet [1].…
Supercritical string theories in D>10 dimensions with no moduli are described, generalizing the asymmetric orientifold construction of one of the authors. By taking the number of dimensions to be large and turning on fluxes, dilaton…
The pole-like accelerated expansion stages purely driven by the coupling between the gravity and the dilaton field without referring to the potential term can be realized in a class of generalized gravity theories. We consider three such…
We investigate the generation of curvature and isocurvature (dilaton, moduli and axion) perturbations in a general class of axion-dilaton-moduli models,including the pre-big bang scenario. Allowing for an arbitrary coupling constant between…
Recently, it has been shown in Ref.[1] that the string thermodynamic fluctuation may lead to a scale invariant spectrum of scalar metric perturbation. However, its realization is still in study. In this note we suppose that the correlation…
We show that if there is a realistic 4-d string, the dilaton and moduli supermultiplets will generically acquire a small mass O(m_{3/2}), providing the only vacuum-independent evidence of low-energy physics in string theory beyond the…
There are no reasons why the singularity in the growth of the dilaton coupling should not be regularised, in a string cosmological context, by the presence of classical inhomogeneities. We discuss a class of inhomogeneous dilaton-driven…
We study dilaton-electrodynamics in flat spacetime and exhibit a set of global cosmic string like solutions in which the magnetic flux is confined. These solutions continue to exist for a small enough dilaton mass but cease to do so above a…
Some of the phenomenological implications of string cosmological models are reviewed, with particular attention to the spectra of the tensor, scalar and vector modes of the geometry. A class of self-dual string cosmological models is…
We consider the cosmological evolution of the three-brane in the background of type IIB string theory. For two different backgrounds which give nontrivial dilaton profile we have derived the Friedman-like equations. These give the…
D-branes, topological defects in string theory on which string endpoints can live, may give new insight into the understanding of the cosmological evolution of the Universe at early epochs. We analyze the dynamics of D-branes in curved…
The existence of a dilaton (or moduli) with gravitational-strength coupling to matter imposes stringent constraints on the allowed energy scale of cosmic strings, $\eta$. In particular, superheavy gauge strings with $\eta \sim 10^{16} GeV$…
Based on a previously derived superstring model possessing a cosmological sector that mimics Starobinsky inflation, we analyze several questions addressed in the recent literature: the generation of an effective $R^2$-term, the stability of…
In this paper we further elaborate on our recently proposed solution to the cosmological constant problem - Phys. Rev. D82 (2010) 044006. One of the elements of the solution is the chameleonic behaviour of the Einstein frame dilaton: the…
The general constraints on the parameter space of soft-breaking terms, in order to avoid dangerous charge and color breaking minima, are applied to the four-dimensional string scenario where the dilaton is the source of supersymmetry…
We present a minimal model for the Universe evolution fully extracted from effective String Theory. By linking this model with a minimal but well established observational information, we prove that it gives realistic predictions on early…