相关论文: Current Acceleration from Dilaton and Stringy Cold…
The detection of dark matter is central to particle physics and cosmology. Current fashionable supersymmetric models provide a dark matter candidate, the lightest supersymmetric particle (LSP). When combined with fairly well understood…
A naive dimensional reduction of the $N=1, D=10$ supergravity theory that naturally arises in five-brane models is used to determine the r\^ole of two fields which are basic ingredients of string models: the dilaton and, among the moduli,…
Using the renormalization-group formalism, a sigma model of a special type- in which the metric and the dilaton depend explicitly on one of the string coordinates only-is investigated near two dimensions. It is seen that dilatonic gravity…
We examine bounds on accelerated expansion in asymptotic regions of the moduli space in string theory compactifications to four spacetime dimensions. While there are conjectures that forbid or constrain accelerated expansion in such…
We give a generic argument that string theory provides a natural setting for warm inflationary cosmology. We then explore a specific model with an inflaton modulus field coupled to fields that provide the continuous dissipation needed for…
I present an outline for cosmological evolution in the framework of string theory with emphasis on a phase of dilaton-driven kinetic inflation. It is shown that a typical background of stochastic gravitational radiation is generated, with…
Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet.…
We discuss fits of unconventional dark energy models to the available data from high-redshift supernovae, distant galaxies and baryon oscillations. The models are based either on brane cosmologies or on Liouville strings in which a…
Amidst all candidates of physics beyond the Standard Model, string theory provides a unique proposal for incorporating gauge and gravitational interactions. In string theory, a four-dimensional theory that unifies quantum mechanics and…
We present a minimal model for the Universe evolution fully extracted from effective String Theory. This model is by its construction close to the standard cosmological evolution, and it is driven selfconsistently by the evolution of the…
Stabilizing all of the modulus fields coming from compactifications of string theory on internal manifolds is one of the outstanding challenges for string cosmology. Here, in a simple example of toroidal compactification, we study the…
We study the formation of black strings from a gravitational collapse of cylindrical dust clouds in the three-dimensional low-energy string theory. New junction conditions for the dilaton as well as two junction conditions for metrics and…
String theory in two-dimensional spacetime illuminates two main threads of recent development in string theory: (1) Open/closed string duality, and (2) Tachyon condensation. In two dimensions, many aspects of these phenomena can be explored…
The purpose of this short review is to present progresses in string theory in the recent past. There have been very important developments in our understanding of string dynamics, especially in the nonperturbative aspects. In this context,…
Explicit string models which can realize inflation and low-energy supersymmetry are notoriously difficult to achieve. Given that sequestering requires very specific configurations, supersymmetric particles are in general expected to be very…
We argue that, for generic string compactifications, dark energy is likely to signal the beginning of the end of our universe, perhaps even through decompactification, with possible implications for the cosmological coincidence problem.…
A string cosmology scenario ("pre-big-bang") postulates that the evolution of the Universe starts from a state of very small curvature and coupling, undergoes a long phase of dilaton-driven kinetic inflation and at some later time joins…
We examine consequences of the stabilization of the dilaton through the axion. An estimate of the resulting dilaton potential yields a relation between the axion parameter $m_a f_{PQ}$ and the average instanton radius, and predicts the…
Inspired by the current observations that the ratio of the abundance of dark energy $\Omega_{\Lambda}$, and the matter density, $\Omega_{m}$, is such that $\Omega_{m}/\Omega_{\Lambda}\sim 0.37$, we provide a string inspired phenomenological…
We present a brief review of recent advances in string cosmology. Starting with the Dilaton-Moduli Cosmology (known also as the Pre Big Bang), we go on to include the effects of axion fields and address the thorny issue of the Graceful Exit…