Related papers: Fuzzy Gravitons From Uncertain Spacetime
We first recall a covariant formalism used to compute conserved charges in gauge invariant theories. We then study the case of gravity for two different boundary conditions, namely spatial infinity and a Brane-World boundary. The new…
In the context of a five-dimensional theory with a scalar field non-minimally-coupled to gravity, we look for solutions that describe novel black-string or maximally-symmetric solutions in the bulk. The brane line-element is found to…
We study the classical geometry associated to fractional D3-branes of type IIB string theory on R^4/Z_2 which provide the gravitational dual for N=2 super Yang-Mills theory in four dimensions. As one can expect from the lack of conformal…
We study the effective geometry felt by the fluctuations of open strings living on the worldvolume of probe D-branes in the presence of background electromagnetic fields. This is captured by an effective action consisting of a Maxwell term…
The general solution of Einstein's gravity equation in $D$ dimensions for an anisotropic and spherically symmetric matter distribution is calculated in a bulk with position dependent cosmological constant. Results for $n$ concentric…
We study seven-brane SU(5) GUT models of string phenomenology which can be consistently analyzed in a purely local framework. The requirement that gravity can decouple constrains the form of four-dimensional physics as well as the geometry…
We propose an approach to formulating string theory in a curved spacetime, which is based on the connection between the states of the WZW model for the isometry group of a background spacetime metric and the representations of the…
We calculate the potential between various configurations of membranes and gravitons in M(atrix) theory. The computed potentials agree with the short distance potentials between corresponding 2-branes and 0-brane configurations in Type IIA…
A thick brane model with Gauss-Bonnet action in a homogeneous anisotropic $D=(4+1+d)$ spacetime is studied. By choosing a concrete metric ansatz, we show that this spacetime is stable against linear tensor perturbations under certain…
Fluxbrane-like backgrounds obtained from flat space by a sequence of T-dualities and shifts of polar coordinates (beta deformations) provide an interesting class of exactly solvable string theories. We compute the one-loop partition…
In this thesis, we discuss the idea of multigravity, namely the possibility that a significant component of gravity that we feel at intermediate distances (1 mm < r < 10^26 cm) is due to massive but ultralight gravitons. We demonstrate how…
Unstable D-branes are central objects in string theory, and exist also in time-dependent backgrounds. In this paper we take first steps to studying brane decay in spacetime orbifolds. As a concrete model we focus on the R^{1,d}/Z_2…
We consider the problem of gravitational forces between point particles on the branes in a Randall-Sundrum (R-S) two brane model with $S^1/Z_2$ symmetry. Matter is assumed to produce a perturbation to the R-S vacuum metric and all the 5D…
Realizing dark energy and the observed de Sitter spacetime in quantum gravity has proven to be obstructed in most every usual approach. We argue that additional degrees of freedom of the left- and right-movers in string theory and a…
All previous Randall-Sundrum type models have required a Z_2 identification source which does not have a known string theoretic origin. We show that the near-horizon of various resolved branes on an Eguchi-Hanson instanton dimensionally…
We construct a string theory realization of the 4+1d quantum Hall effect recently discovered by Zhang and Hu. The string theory picture contains coincident D4-branes forming an S^4 and having D0-branes (i.e. instantons) in their…
In this work, the influence of the boundary term $B$ is analyzed in a string-like thick brane scenario in the gravity context $f(T, B)$. For that, three models of $f(T, B)$ are proposed, i.e., $f_1(T, B)=T+k{B}^{n}$, $f_2(T,…
First we contemplate the operational definition of space-time in four dimensions in light of basic principles of quantum mechanics and general relativity and consider some of its phenomenological consequences. The quantum gravitational…
We investigate the `giant gravitons' of McGreevy, Susskind and Toumbas [hep-th/0003075]. We demonstrate that these are BPS configurations which preserve precisely the same supersymmetries as a `point-like' graviton. We also show that there…
We propose a quantum theory of membranes designed such that the ground-state wavefunction of the membrane with compact spatial topology \Sigma_h reproduces the partition function of the bosonic string on worldsheet \Sigma_h. The…