Geometrodynamical Formulation of Two-Dimensional Dilaton Gravity

Two-dimensional matterless dilaton gravity with arbitrary dilatonic potential can be discussed in a unitary way, both in the Lagrangian and canonical frameworks, by introducing suitable field redefinitions. The new fields are directly related to the original spacetime geometry and in the canonical picture they generalize the well-known geometrodynamical variables used in the discussion of the Schwarzschild black hole. So the model can be quantized using the techniques developed for the latter case. The resulting quantum theory exhibits the Birkhoff theorem at the quantum level.Comment: 15 pages, LATE

Stability of naked singularities and algebraically special modes

We show that algebraically special modes lead to the instability of naked singularity spacetimes with negative mass. Four-dimensional negative-mass Schwarzschild and Schwarzschild-de Sitter spacetimes are unstable. Stability of the Schwarzschild-anti-de Sitter spacetime depends on boundary conditions. We briefly discuss the generalization of these results to charged and rotating singularities.Comment: 6 pages. ReVTeX4. v2: Minor improvements and extended discussion on boundary conditions. Version to appear in Phys. Rev.

Pre-big bang in M-theory

We discuss a simple cosmological model derived from M-theory. Three assumptions lead naturally to a pre-big bang scenario: (a) 11-dimensional supergravity describes the low-energy world; (b) non-gravitational fields live on a three-dimensional brane; and (c) asymptotically past triviality.Comment: 16 pages, 8 figures, LaTeX (requires epsf

Spinor couplings to dilaton gravity induced by the dimensional reduction of topologically massive gravity

A Dirac spinor is coupled to topologically massive gravity and the D=3 dimensional action is reduced to D=2 dimensions with a metric that includes both the electromagnetic potential 1-form A and a dilaton scalar \phi. The dimensionnaly reduced spinor is made a mass eigenstate with a (local) chiral rotation. The non-trivial interactions thus induced are discussed.Comment: 8 pages, no figure

Black hole particle emission in higher-dimensional spacetimes

In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption cross-sections, the relative emissivities and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in models with extra dimensions and black hole detection in particle colliders.Comment: 4 pages, RevTeX 4. v3: Misprints in Tables correcte

Signatures of black holes at the LHC

Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.Comment: 13 pages, 7 figure

Catfish: A Monte Carlo simulator for black holes at the LHC

We present a new Fortran Monte Carlo generator to simulate black hole events at CERN's Large Hadron Collider. The generator interfaces to the PYTHIA Monte Carlo fragmentation code. The physics of the BH generator includes, but not limited to, inelasticity effects, exact field emissivities, corrections to semiclassical black hole evaporation and gravitational energy loss at formation. These features are essential to realistically reconstruct the detector response and test different models of black hole formation and decay at the LHC.Comment: 22 pages, 8 eps figures. Matches version already published in Computer Physics Communications. CATFISH code and documentation are available at http://www.phy.olemiss.edu/GR/catfis

Quantum Electromagnetic Wormholes and Geometrical Description of the Electric Charge

I present and discuss a class of solutions of the Wheeler-de Witt equation describing wormholes generated by coupling of gravity to the electromagnetic field for Kantowski-Sachs and Bianchi I spacetimes. Since the electric charge can be viewed as electric lines of force trapped in a finite region of spacetime, these solutions can be interpreted as the quantum corresponding of the Ein\-stein\--Ro\-sen\--Mis\-ner\--Whee\-ler electromagnetic geon.Comment: 13 pages, PLAIN TEX, Report No: SISSA 92/94/A (to appear in Phys. Rev. D15

The AdS/CFT correspondence in two dimensions

We review recent progress in understanding the anti-de Sitter/conformal field theory correspondence in the context of two-dimensional dilaton gravity theory.Comment: Contribution to the Proceedings of the Euroconference on "Brane New World and Noncommutative Geometry", Turin, October 200

Gravitational Larmor formula in higher dimensions

The Larmor formula for scalar and gravitational radiation from a pointlike particle is derived in any even higher-dimensional flat spacetime. General expressions for the field in the wave zone and the energy flux are obtained in closed form. The explicit results in four and six dimensions are used to illustrate the effect of extra dimensions on linear and uniform circular motion. Prospects for detection of bulk gravitational radiation are briefly discussed.Comment: 5 pages, no figure