Related papers: Brane Cosmology from Heterotic String Theory
We study the induced 4-dimensional linearized Einstein field equations in an m-dimensional bulk space by means of a confining potential. It is shown that in this approach the mass of graviton is quantized. The cosmological constant problem…
We consider deformations of the singular "global cosmic string" compactifications, known to naturally generate exponentially large scales. The deformations are obtained by allowing a constant curvature metric on the brane and correspond to…
We argue that traditional methods of compactification of string theory make it very difficult to understand how the cosmological constant becomes zero. String inspired models can give zero cosmological constant after fine tuning but since…
We study a 6-dimensional brane world model with an abelian string residing in the two extra dimensions. We study both static as well as inflating branes and find analytic solutions for the case of trivial matter fields in the bulk. Next to…
We examine the issue of the cosmological constant in the $many$ $inflating$ branes scenario, extending on two recent models by I.Oda and Randall-Sundrum. The exact solution in a closed form is found in the slow roll approximation of the…
Starting from a completely general standpoint, we find the most general brane-Universe solutions for a three-brane in a five dimensional spacetime. The brane can border regions of spacetime with or without a cosmological constant. Making no…
We consider, in 5 dimensions, the low energy effective action induced by heterotic string theory including the leading stringy correction of order alpha'. In the presence of a single positive tension flat brane, and an infinite extra…
We comment on approaches to the Cosmological Constant Problem in 4+1 dimensions, with the Standard Model fields confined to a 3-brane. We show that requiring maximal 4D symmetry only on this 3-brane (and not on all other 3-branes that…
If the fifth dimension is one-dimensional connected manifold, up to diffeomorphic, the only possible space-time will be $M^4 \times R^1$, $M^4 \times R^1/Z_2$, $M^4 \times S^1$ and $M^4 \times S^1/Z_2$. And there exist two possibilities on…
The presence of a cosmological constant, Lambda, in an action with higher powers of the curvature can produce rapidly oscillating metrics. We develop a perturbative approach for generating periodic solutions to the non-linear field…
We consider the metrics for cosmic strings and $p$-branes in spacetime dimension $N>4$, that is, we look for solutions to Einstein-Maxwell-Dilaton gravity in $N$-dimensions with boost symmetry in the $p$-directions along the brane.…
In this paper a general solution is found for a five dimensional orbifold spacetime that induces a $k=0$ cosmology on a three-brane. Expressions for the energy density and pressure on the brane in terms of the brane metric are derived.…
We consider maximally symmetric 3-branes embedded in a six-dimensional bulk spacetime with Lovelock dynamics. We study the properties of the solutions with respect to their induced curvature, their vacuum energy and their effective…
Gravitational properties of a hedge-hog type topological defect in two extra dimensions are considered in General Relativity employing a vector as the order parameter. The developed macroscopic theory of phase transitions with spontaneous…
We consider some classes of solutions of the static, spherically symmetric gravitational field equations in the vacuum in the brane world scenario, in which our Universe is a three-brane embedded in a higher dimensional space-time. The…
General model of multidimensional $R^2$-gravity including Riemann tensor square term (non-zero $c$ case) is considered. The number of brane-worlds in such model is constructed (mainly in five dimensions) and their properties are discussed.…
We model the universe as a 3-brane embedded in five dimensional spacetime with N=2 supersymmetry. The presence of the scalar fields of the universal hypermultiplet in the bulk results in a positive pressure effectively reducing the value of…
We build a number of integrable one--scalar spatially flat cosmologies, which play a natural role in inflationary scenarios, examine their behavior in several cases and draw from them some general lessons on this type of systems, whose…
We study brane-world solutions of five-dimensional supergravity in singular spaces. We exhibit a self-tuned four-dimensional cosmological constant when five-dimensional supergravity is broken by an arbitrary tension on the brane-world. The…
The possibility to study the M/string theory cosmology via 5d bulk & brane action is investigated. The role of the 4-form field in the theory of BPS branes in 5d is clarified. We describe arguments suggesting that the effective 4d…