54 research outputs found
The action for higher spin black holes in three dimensions
In the context of (2+1)--dimensional Chern-Simons SL(N,R)\times SL(N,R) gauge
fields and spin N black holes we compute the on-shell action and show that it
generates sensible and consistent thermodynamics. In particular, the
Chern-Simons action solves the integrability conditions recently considered in
the literature.Comment: Paper shortened and generalized. Main results unchanged. 25 pages,
Latex, no figure
Bianchi Cosmological Models and Gauge Symmetries
We analyze carefully the problem of gauge symmetries for Bianchi models, from
both the geometrical and dynamical points of view. Some of the geometrical
definitions of gauge symmetries (=``homogeneity preserving diffeomorphisms'')
given in the literature do not incorporate the crucial feature that local gauge
transformations should be independent at each point of the manifold of the
independent variables ( = time for Bianchi models), i.e, should be arbitrarily
localizable ( in time). We give a geometrical definition of homogeneity
preserving diffeomorphisms that does not possess this shortcoming. The proposed
definition has the futher advantage of coinciding with the dynamical definition
based on the invariance of the action ( in Lagrangian or Hamiltonian form). We
explicitly verify the equivalence of the Lagrangian covariant phase space with
the Hamiltonian reduced phase space. Remarks on the use of the Ashtekar
variables in Bianchi models are also given.Comment: 16 pages, Latex file, ULB-PMIF-92/1
Orientifolded Locally AdS3 Geometries
Continuing the analysis of [arXiv:1003.4089[hep-th]], we classify all locally
AdS3 stationary axi-symmetric unorientable solutions to AdS3 Einstein gravity
and show that they are obtained by applying certain orientifold projection on
AdS3, BTZ or AdS3 self-dual orbifold, respectively O-AdS3, O-BTZ and O-SDO
geometries. Depending on the orientifold fixed surface, the O-surface, which is
either a space-like 2D plane or cylinder, or a light-like 2D plane or cylinder
one can distinguish four distinct cases. For the space-like orientifold plane
or cylinder cases these geometries solve AdS3 Einstein equations and are hence
locally AdS3 everywhere except at the O-surface, where there is a
delta-function source. For the light-like cases the geometry is a solution to
Einstein equations even at the O-surface. We discuss the causal structure for
static, extremal and general rotating O-BTZ and O-SDO cases as well as the
geodesic motion on these geometries. We also discuss orientifolding Poincare
patch AdS3 and AdS2 geometries as a way to geodesic completion of these spaces
and comment on the 2D CFT dual to the O-geometries.Comment: 26 page, 4 .eps figure
Asymptotic symmetries in 3d gravity with torsion
We study the nature of asymptotic symmetries in topological 3d gravity with
torsion. After introducing the concept of asymptotically anti-de Sitter
configuration, we find that the canonical realization of the asymptotic
symmetry is characterized by the Virasoro algebra with classical central
charge, the value of which is the same as in general relativity: c=3l/2G.Comment: 25 pages, RevTeX, no figure
Anti-de Sitter/CFT Correspondence in Three-Dimensional Supergravity
Anti-de Sitter supergravity models are considered in three dimensions.
Precise asymptotic conditions involving a chiral projection are given on the
Rarita-Schwinger fields. Together with the known boundary conditions on the
bosonic fields, these ensure that the asymptotic symmetry algebra is the
superconformal algebra. The classical central charge is computed and found to
be equal to the one of pure gravity. It is also indicated that the asymptotic
degrees of freedom are described by 2D "induced supergravity" and that the
boundary conditions "transmute" the non-vanishing components of the WZW
supercurrent into the supercharges.Comment: Additional remarks in the extended case, added references, and small
misprints corrected. To appear in Phys. Rev. D. Latex, 19 pages, no figure
Asymptotic dynamics in 3D gravity with torsion
We study the nature of boundary dynamics in the teleparallel 3D gravity. The
asymptotic field equations with anti-de Sitter boundary conditions yield only
two non-trivial boundary modes, related to a conformal field theory with
classical central charge. After showing that the teleparallel gravity can be
formulated as a Chern-Simons theory, we identify dynamical structure at the
boundary as the Liouville theory.Comment: 16 pages, RevTeX, no figure
Exploring Three-dimensional Higher-Spin Supergravity based on sl(N |N - 1) Chern-Simons theories
We investigate various aspects of higher-spin anti-de Sitter supergravity in
three dimensions as described by Chern-Simons theory based on the
finite-dimensional superalgebra sl(N |N - 1), with the particular case of N = 3
as our prime example. This class of theories serves as a natural
supersymmetrization of the higher-spin gravity theory based on sl(N)
Chern-Simons theories. We demonstrate explicitly that the asymptotic symmetry
algebra contains the N = 2 superconformal algebra in each sector. The
appropriate Killing spinor equations are derived and used to classify existing
and new classical solutions. We also discuss holonomy conditions, higher-spin
black holes and conical defect spacetimes in this class of theories.Comment: 41 pages, a few typos in v4 correcte
Hidden sl(2,R) Symmetry in 2D CFTs and the Wave Function of 3D Quantum Gravity
We show that all two-dimensional conformal field theories possess a hidden
sl(2,R) affine symmetry. More precisely, we add appropriate ghost fields to an
arbitrary CFT, and we use them to construct the currents of sl(2,R). We then
define a BRST operator whose cohomology defines a physical subspace where the
extended theory coincides with the original CFT. We use the sl(2,R) algebra to
construct candidate wave functions for 3-d quantum gravity coupled to matter,
and we discuss their viability.Comment: Minor misprints corrected.Eight references added. To appear in
JHEP.34 pages, LaTe
Einstein billiards and spatially homogeneous cosmological models
In this paper, we analyse the Einstein and Einstein-Maxwell billiards for all
spatially homogeneous cosmological models corresponding to 3 and 4 dimensional
real unimodular Lie algebras and provide the list of those models which are
chaotic in the Belinskii, Khalatnikov and Lifschitz (BKL) limit. Through the
billiard picture, we confirm that, in D=5 spacetime dimensions, chaos is
present if off-diagonal metric elements are kept: the finite volume billiards
can be identified with the fundamental Weyl chambers of hyperbolic Kac-Moody
algebras. The most generic cases bring in the same algebras as in the
inhomogeneous case, but other algebras appear through special initial
conditions.Comment: 27 pages, 10 figures, additional possibility analysed in section 4.3,
references added, typos correcte
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