Related papers: Towards p-Adic Matter in the Universe

In the context of a cosmological string model describing the propagation of strings in a time-dependent Robertson-Walker background space-time, we show that the asymptotic acceleration of the Universe can be identified with the square of…

We give an introductory account of the AdS/CFT correspondence in the 1/2-BPS sector of ${\cal N}=4$ super Yang-Mills theory.Six of the dimensions of the string theory are emergent in the Yang-Mills theory. In this article we suggest how…

Spacetime non-commutativity appears in string theory. In this paper, the non-commutativity in string theory is reviewed. At first we review that a Dp-brane is equivalent to a configuration of infinitely many D($p-2$)-branes. If we consider…

We present qualitative evidence that closed string tachyon solitons describe backgrounds of lower-dimensional sub-critical string theory. We show that a co-dimension one soliton in the low energy effective gravity-dilaton-tachyon theory in…

We analyze the space-time structure of local gauge string with a phenomenological energy momentum tensor, as prescribed by Vilenkin in an arbitrary number of space-time dimensions with a non-zero cosmological constant >. A set of solutions…

It is well known that string theories naturally compactify on anti-de Sitter spaces, and yet cosmological observations show no evidence of a negative cosmological constant in the early Universe's evolution. In this letter we present two…

We study the dynamics of circular cosmic string loops in a spatially flat Friedmann Lema\^itre Robertson Walker universe within a fractional Polyakov framework that incorporates nonlocal memory effects. Allowing both the loop radius and…

Beginning with a review of the arguments leading to the so-called c=1 barrier in the continuum formulation of noncritical string theory, the pathology is then exhibited in a discretized version of the theory, formulated through dynamical…

I review several aspects of torsion in string-inspired cosmologies. In particular, I discuss its connection with fundamental, string-model independent, axion fields associated with the massless gravitational multiplet of the string. I argue…

Redefining the vacuum state of a free twofold N=1 covariant supersymmetric string action as the one with all the world sheet fermionic excited states occupied, makes the theory anomaly free in D=4 with Minkowski signature. The theory thus…

We extend the non-perturbative time-dependent bosonic string action of [3] to a N=1 supersymmetric world sheet action with graviton background, and assume a superpotential, function of the time super coordinate.

The consistency of string theory as a theory of gravity does not rely on the presence of spacetime supersymmetry; however, its absence leads to the emergence of tadpole diagrams in the on-shell worldsheet formulation, thus undermining our…

We extend the system of ungauged N=2, d=4 supergravity coupled to vector multiplets and hypermultiplets with 2-form potentials. The maximal number of 2-form potentials that one may introduce is equal to the number of isometries of either…

In the modified measure formulation the string tension appear as an additional dynamical degree of freedom and these tensions are not universal, but rather each string generates its own tension, which can have a different value for each…

We study cosmological effects of homogeneous tachyon field as dark energy. We concentrate on two different scalar field potentials, the inverse square potential and the exponential potential. These models have a unique feature that the…

We suggest that the universe filled with unstable D-branes in their rolling tachyon vacuum state, described by periodic arrays of D-instantons along the imaginary time direction, may be a natural background for formulating string theory.…

This article reviews recent developments in the study of universes with a positive cosmological constant in string theory.

We review some recent developments in string theory, emphasizing the importance of vacuum instabilities, their relation to the density of states, and the role of space-time fermions in non-critical string theory. We also discuss the…

Evolution of a universe with homogeneous extra dimensions is studied with the benefit of a well-chosen parameter space that provides a systematic, useful, and convenient way for analysis. In this model we find a natural evolution pattern…

We review recent developments on nonrelativistic string theory. In flat spacetime, the theory is defined by a two-dimensional relativistic quantum field theory with nonrelativistic global symmetries acting on the worldsheet fields. This…