The standard Einstein-Maxwell equations in 2+1 spacetime dimensions, with a negative cosmological constant, admit black hole solution. hole---characterized by mass, angular momentum, and charge, defined flux integrals at infinity---is quite similar to its 3+1 counterpart. Anti--de Sitter space appears as energy state separated mass gap from the continuous spectrum. Evaluation of partition function yields that entropy is equal twice perimeter length horizon.

The geometry of the spinning black holes standard Einstein theory in 2+1 dimensions, with a negative cosmological constant and without couplings to matter, is analyzed detail. It shown that hole arises from identifications points anti-de Sitter space by discrete subgroup $SO(2,2)$. generic smooth manifold metric sense. surface $r=0$ not curvature singularity but, rather, causal structure. Continuing past it would introduce closed timelike lines. However, simple examples show regularity at be...

We show that intermediate mass black holes conjectured to be the early precursors of supermassive and surrounded by relic cold dark matter density spikes can act as particle accelerators with collisions, in principle, at arbitrarily high centre energies case Kerr holes. While ejecta from such interactions will highly redshifted, we may anticipate possibility a unique probe Planck-scale physics.

We resurrect Eddington's proposal for the gravitational action in presence of a cosmological constant and extend it to include matter fields. show that Newton-Poisson equation is modified sources charged black holes great similarities with those arising Born-Infeld electrodynamics coupled gravity. When we consider homogeneous isotropic space-times find there minimum length (and maximum density) at early times, clearly pointing an alternative theory Big Bang. thus argue modern formulation...

We review some aspects of three-dimensional quantum gravity with emphasis in the `CFT -> Geometry' map that follows from Brown-Henneaux conformal algebra. The general solution to classical equations motion anti-de Sitter boundary conditions is displayed. This parametrized by two functions which become Virasoro operators after quantisation. A space states solutions exhibited. Some recent proposals understand Bekenstein-Hawking entropy are reviewed this context. origin degrees freedom arising...

Static, spherically symmetric solutions of the field equations for a particular dimensional continuation general relativity with negative cosmological constant are studied. The action is, in odd dimensions, Chern-Simons form anti-de Sitter group and, even Euler density constructed Lorentz part curvature tensor. Both actions special cases Lovelock action, and they reduce to Hilbert (with constant) lower $\mbox{$\cal D$}=3$ D$}=4$. Exact black hole characterized by mass ($M$) electric charge...

The Euclidean black hole has topology ${\mathit{gerR}}^{2}$\ifmmode\times\else\texttimes\fi{}${\mathit{scrS}}^{\mathit{d}\mathrm{\ensuremath{-}}2}$. It is shown that, in Einstein's theory the deficit angle of a cusp at any point ${\mathit{gerR}}^{2}$ and area ${\mathit{scrS}}^{\mathit{d}\mathrm{\ensuremath{-}}2}$ are canonical conjugates. entropy emerges as Euler class small disk centered horizon multiplied by there. These results obtained through dimensional continuation Gauss-Bonnet...

We use the Regge-Teitelboim method to treat surface integrals in gauge theories find global charges Chern-Simons theory. derive affine and Virasoro generators as associated with symmetries of boundary. The role boundary conditions is clarified. prove that for diffeomorphisms do not preserve there a classical contribution central charge algebra. example anti--de Sitter 2+1 gravity considered detail.

A bstract We show that AdS amplitudes are CFT correlators to all orders in the loop expansion by showing they obey conformal Ward identities. In particular, we provide explicit formulas for constants and functions of cross-ratios determine terms bulk data.

The escape fraction at infinity is evaluated for massless particles produced in collisions of weakly interacting accreted into a density spike near the particle horizon an extremal Kerr black hole, case equatorial orbits. We compare with Schwarzschild case, and argue that holes, redshifted signatures can be could potentially explore physics center mass energies extend beyond those any feasible terrestrial accelerator.

We study the dynamics of homogeneous, isotropic universes which are governed by Eddington-inspired alternative theory gravity has a single extra parameter, $\ensuremath{\kappa}$. Previous results showing singularity-avoiding behavior for $\ensuremath{\kappa}>0$ found to be upheld in case domination perfect fluid with equation state parameter $w>0$. The range $\ensuremath{-}\frac{1}{3}<w<0$ is lead experience unbounded expansion rates while still at finite density. In $\ensuremath{\kappa}<0$...

In this paper we consider an extension to Eddington's proposal for the gravitational action. We study tensor perturbations of a homogeneous and isotropic space-time in Eddington regime, where modifications Einstein gravity are strong. find that mode is linearly unstable deep regime discuss its cosmological implications.

A Chern-Simons action for supergravity in odd-dimensional spacetimes is proposed. For all odd dimensions, the local symmetry group a non trivial supersymmetric extension of Poincar\'e group. In $2+1$ dimensions gauge reduces to super-Poincar\'e, while $D=5$ it super-Poincar\'e with central charge. general, obtained by addition 1-form field which transforms as an antisymmetric fifth-rank tensor under Lorentz rotations. Since Lagrangian density supergroup, supersymmetry algebra closes off...

Constant curvature black holes are constructed by identifying points in anti--de Sitter space. In $n$ dimensions, the resulting topology is ${\mathfrak{R}}^{n\ensuremath{-}1}\ifmmode\times\else\texttimes\fi{}{S}_{1}$, as opposed to usual ${\mathfrak{R}}^{2}\ifmmode\times\else\texttimes\fi{}{S}_{n\ensuremath{-}2}$ Schwarzschild hole, and corresponding causal structure displayed an $(n\ensuremath{-}1)$-dimensional picture, two-dimensional Kruskal diagram. The five-dimensional case, which can...

We construct G\"odel-type black hole and particle solutions to Einstein-Maxwell theory in $2+1$ dimensions with a negative cosmological constant Chern-Simons term. On-shell, the electromagnetic stress-energy tensor effectively replaces by minus square of topological mass produces pressure-free perfect fluid. show how particular solution is related original G\"odel universe analyze from point view identifications. Finally, we compute conserved charges work out thermodynamics.

It has been argued that a Universe governed by Eddington-Born-Infeld gravity can be compatible with current cosmological constraints. The extra fields introduced in this theory behave as both dark matter and energy, unifying the sector one coherent framework. We show various roles play expansion of study evolution linear perturbations regimes. find that, unified sector, will lead to excessive fluctuations cosmic microwave background on large scales. In presence constant, however, form...

It is known that the center-of-mass energy of collision two massive particles following geodesics around a black hole presents maximum. The maximum increases when endowed with spin, and for maximally rotating this blows up, offering, in principle, unique probe fundamental physics. This work extends latter studies by considering colliding possess intrinsic angular momentum (spin), described Hanson–Regge–Hojman theory spinning particles. By analyzing planar trajectories non-rotating holes,...

Anti-de Sitter space with identified points give rise to black-hole structures. This was first pointed out in three dimensions and generalized higher by Aminneborg et al. In this paper, we analyse several aspects of the five-dimensional anti-de black hole, including its relation thermal space, embedding a Chern - Simons supergravity theory, global charges holonomies existence Killing spinors.

We argue that Einstein gravity coupled to a Born-Infeld theory provides an attractive candidate represent dark matter and energy. For cosmological models, the field has equation of state which interpolates between matter, $p=0$ (small times), constant $p=\ensuremath{-}\ensuremath{\rho}$ (large times). On galactic scales, predicts asymptotically flat rotation curves.

We study the parity-breaking higher-curvature gravity theory of Chern-Simons (CS), using Palatini formulation in which metric and connection are taken to be independent fields. first show that CS leads first-order derivative equations motion thus avoid typical instabilities formalism. As an initial application, we analyze cosmological propagation gravitational waves (GWs) gravity. that, due parity breaking, polarizations GWs suffer two effects during propagation: amplitude birefringence...