We first obtain the analogue of Vaidya’s solution on the brane for studying the collapse of null fluid onto a flat Minkowski cavity on the brane. Since the backreaction of the bulk onto the brane is supposed to strengthen gravity on the brane, it would favour formation of black hole as against naked singularity. That is the parameter window in the initial data set giving rise to naked singulari...

The number of configurations of the dynamical triangulation model of 4D euclidean quantum gravity appears to grow faster than exponentially with the volume, with the implication that the system would end up in the crumpled phase for any fixed κ2 (inverse bare Newton constant). However, a scaling region is not excluded if we allow κ2 to go to infinity together with the volume. email: [email protected]...

We discuss the \gravitationally dressed" beta functions in the Gross{ Neveu model interacting with 2d Liouville theory and in SU(N) gauge theory interacting with the conformal sector of 4d quantum gravity. Among the e ects that we suggest may feel the gravitational dressing are the minimum of the e ective potential and the running of the gauge coupling. [email protected] percacci@tsmi19....

We show that the Gauss-Bonnet term is the only consistent curvature squared interaction in the Randall-Sundrum model and various static and inflationary solutions can be found. And from metric perturbations around the RS background with a single brane embedded, we also show that for a vanishing Gauss-Bonnet coefficient, the brane bending allows us to reproduce the 4D Einstein gravity at the lin...

A bstract The validity of the Coleman mechanism, which automatically tunes fundamental constants, is examined in two-dimensional and four-dimensional quantum gravity theories. First, we consider Euclidean on orientable closed manifolds coupled to conformal matter central charge c ≤ 1. proper time Hamiltonian this system known be written as a field theory noncritical strings, can also viewed thi...