Related papers: Dilaton, winding modes and cosmological solutions

The scenario that the Universe contracts towards a big crunch and then undergoes a transition to expanding Universe in envisaged in the quantum string cosmology approach. The Wheeler-De Witt equation is solved exactly for an exponential…

Finding a consistent way to stabilize the various moduli fields which generically appear in string theory compactifications, is essential if string theory is to make contact with the physics we see around us. We present, in this paper, a…

We construct new classes of exact cosmological solutions to five dimensional Einstein-Maxwell-dilaton theory with two coupling constants for the dilaton-Maxwell term and dilaton-cosmological constant term. All the solutions are…

In this paper free quantum theories are derived solely from their underlying symmetry group without reference to a Lagrangean or classical physics and then interactions are introduced by making use of automorphism of the symmetry algebra.…

We extend the formulation of spin 2 fields on Minkowski space which makes the action manifestly invariant under duality rotations to the case of interactions with external electric and magnetic sources by adding suitable potentials for the…

We review various aspects of de Sitter spacetime in string theory: its status as an effective field theory spacetime solution, its relation to the vacuum energy problem in string theory, its (global) holographic definition in terms of two…

Within the context of a super-critical (Liouville) string, we discuss (target-space) two-dimensional string cosmology. A numerical analysis indicates that the identification of time with the Liouville mode results in an expanding universe…

We show that a pair of field theory monodromies in which the shift symmetry is broken by small, well motivated deformations, naturally incorporates a mechanism for cancelling off radiative corrections to the cosmological constant. The…

The solutions that describe the motion of the classical simple pendulum have been known for very long time and are given in terms of elliptic functions, which are doubly periodic functions in the complex plane. The independent variable of…

We obtain cosmological four dimensional solutions of the low energy effective string theory by reducing a five dimensional black hole, and black hole--de Sitter solution of Einstein gravity down to four dimensions. The appearance of a…

We complete the proof of the ghost-dilaton theorem in string theory by showing that the coupling constant dependence of the vacuum vertices appearing in the closed string action is given correctly by one-point functions of the…

Theories of the cosmological constant fall into two classes, those in which the vacuum energy is fixed by the fundamental theory and those in which it is adjustable in some way. For each class we discuss key challenges. The string theory…

The existence of point symmetries in the cosmological field equations of generalized vacuum scalar--tensor theories is considered within the context of the spatially homogeneous cosmologies. It is found that such symmetries only occur in…

We verify that the dilaton together with one exactly marginal field, form a moduli space of marginal deformations of closed bosonic string field theory to polynomial order five. We use the results of this successful check in order to find…

String cosmology solutions are examined in a generalized phase-space including sources representing arbitrary corrections to lowest order string-dilaton-gravity effective action. We find a set of necessary conditions for a graceful exit…

We investigate a string theoretic cosmological model in the context of the gauged Wess-Zumino-Witten model. Our model is based on a product of non-compact coset space and a spectator flat space; $[SL(2,R)/U(1)]_k \times {\bf R}^2$. We…

We examine some novel physical consequences of the general structure of moduli spaces of string vacua. These include (1) finiteness of the volume of the moduli space and (2) chaotic motion of the moduli in the early universe. To fix ideas…

A supersymmetric approach to string quantum cosmology based on the non-compact, global duality symmetries of the effective action is developed. An N=2 supersymmetric action is derived whose bosonic component is the…

We consider a codimension-one brane embedded in a gravity-dilaton bulk action, whose symmetries are compatible with T-duality along the space-like directions parallel to the brane, and the bulk time-like direction. The equations of motions…

We investigate the nature of ordinary cosmic vortices in some scalar-tensor extensions of gravity. We find solutions for which the dilaton field condenses inside the vortex core. These solutions can be interpreted as raising the degeneracy…