835 research outputs found
Combinatorial and topological phase structure of non-perturbative n-dimensional quantum gravity
We provide a non-perturbative geometrical characterization of the partition
function of -dimensional quantum gravity based on a coarse classification of
riemannian geometries. We show that, under natural geometrical constraints, the
theory admits a continuum limit with a non-trivial phase structure parametrized
by the homotopy types of the class of manifolds considered. The results
obtained qualitatively coincide, when specialized to dimension two, with those
of two-dimensional quantum gravity models based on random triangulations of
surfaces.Comment: 13 page
On the Black-Hole Conformal Field Theory Coupled to the Polyakov's String Theory. A Non Perturbative Analysis
We couple the 2D black-hole conformal field theory discovered by Witten to a
dimensional Euclidean bosonic string. We demonstrate that the resulting
planar (=zero genus) string susceptibility is real for any .Comment: 5 page
A generalized model for two dimensional quantum gravity and dynamics of random surfaces for d>1
The possible interpretations of a new continuum model for the two-dimensional
quantum gravity for (=matter central charge), obtained by carefully
treating both diffeomorphism and Weyl symmetries, are discussed. In particular
we note that an effective field theory is achieved in low energy (large area)
expansion, that may represent smooth self-avoiding random surfaces embedded in
a -dimensional flat space-time for arbitrary . Moreover the values of
some critical exponents are computed, that are in agreement with some recent
numerical results.Comment: n. 11; Phyzz
Mean Field Approach to the Giant Wormhole Problem
We introduce a gaussian probability density for the space-time distribution
of wormholes, thus taking effectively into account wormhole interaction. Using
a mean-field approximation for the free energy, we show that giant wormholes
are probabilistically suppressed in a homogenous isotropic ``large'' universe.Comment: 10 pages, Late
On the Stability of a Stringy Black Hole
We study the stability under perturbations of a charged four dimensional
stringy black hole arising from gauging a previously studied WZW model. We find
that the black hole is stable only in the extremal case .Comment: 14 pages + 1 figure (not included but available on request
- …