56 research outputs found
Holographic entropy of Warped-AdS black holes
We study the asymptotic symmetries of three-dimensional Warped Anti-de Sitter
(WAdS) spaces in three-dimensional New Massive Gravity (NMG). For a specific
choice of asymptotic boundary conditions, we find that the algebra of charges
is infinite-dimensional and coincides with the semidirect sum of Virasoro
algebra with non-vanishing central charge and an affine
Ka\v{c}-Moody algebra. We show that the WAdS black hole configurations organize
in terms of two commuting Virasoro algebras. We identify the Virasoro
generators that expand the associated representations in the dual Warped
Conformal Field Theory (WCFT) and, by applying the Warped version of the Cardy
formula, we prove that the microscopic WCFT computation exactly reproduces the
entropy of black holes in WAdS space.Comment: 13 pages. v2 minor typos correcte
Celestial holography: An asymptotic symmetry perspective
We review the role that infinite-dimensional symmetries arising at the
boundary of asymptotically flat spacetimes play in the context of the celestial
holography program. Once recast into the language of conformal field theory,
asymptotic symmetries provide key constraints on the sought-for celestial dual
to quantum gravity in flat spacetimes.Comment: Invited review for Physics Reports (preprint), 79 pages, 7 figure
Asymptotic symmetries and dynamics of three-dimensional flat supergravity
A consistent set of asymptotic conditions for the simplest supergravity
theory without cosmological constant in three dimensions is proposed. The
canonical generators associated to the asymptotic symmetries are shown to span
a supersymmetric extension of the BMS algebra with an appropriate central
charge. The energy is manifestly bounded from below with the ground state given
by the null orbifold or Minkowski spacetime for periodic, respectively
antiperiodic boundary conditions on the gravitino. These results are related to
the corresponding ones in AdS supergravity by a suitable flat limit. The
analysis is generalized to the case of minimal flat supergravity with
additional parity odd terms for which the Poisson algebra of canonical
generators form a representation of the super-BMS algebra with an
additional central charge.Comment: 13 pages, no figure
Supertranslations and Superrotations at the Black Hole Horizon
We show that the asymptotic symmetries close to nonextremal black hole
horizons are generated by an extension of supertranslations. This group is
generated by a semidirect sum of Virasoro and Abelian currents. The charges
associated with the asymptotic Killing symmetries satisfy the same algebra.
When considering the special case of a stationary black hole, the zero mode
charges correspond to the angular momentum and the entropy at the horizon.Comment: 6 pages, references added, published versio
Extended symmetries at the black hole horizon
We prove that non-extremal black holes in four-dimensional general relativity exhibit an infinite-dimensional symmetry in their near horizon region. By prescribing a physically sensible set of boundary conditions at the horizon, we derive the algebra of asymptotic Killing vectors, which is shown to be infinite-dimensional and includes, in particular, two sets of supertranslations and two mutually commuting copies of the Virasoro algebra. We define the surface charges associated to the asymptotic diffeomorphisms that preserve the boundary conditions and discuss the subtleties of this definition, such as the integrability conditions and the correct definition of the Dirac brackets. When evaluated on the stationary solutions, the only non-vanishing charges are the zero-modes. One of them reproduces the Bekenstein-Hawking entropy of Kerr black holes. We also study the extremal limit, recovering the NHEK geometry. In this singular case, where the algebra of charges and the integrability conditions get modified, we find that the computation of the zero-modes correctly reproduces the black hole entropy. Furthermore, we analyze the case of three spacetime dimensions, in which the integrability conditions notably simplify and the field equations can be solved analytically to produce a family of exact solutions that realize the boundary conditions explicitly. We examine other features, such as the form of the algebra in the extremal limit and the relation to other works in the literature.Fil: Donnay, Laura. UniversitĂ© Libre de Bruxelles; BĂ©lgicaFil: Giribet, Gaston Enrique. UniversitĂ© Libre de Bruxelles; BĂ©lgica. Pontificia Universidad CatĂłlica de ValparaĂso; Chile. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de FĂsica de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FĂsica de Buenos Aires; ArgentinaFil: González, Alejandro Hernán. UniversitĂ© Libre de Bruxelles; BĂ©lgicaFil: Pino, Miguel. Universidad de Santiago de Chile; Chil
-Forms on the Celestial Sphere
We construct a basis of conformal primary wavefunctions (CPWs) for -form
fields in any dimension, calculating their scalar products and exhibiting the
change of basis between conventional plane wave and CPW mode expansions. We
also perform the analysis of the associated shadow transforms. For each family
of -form CPWs, we observe the existence of pure gauge wavefunctions of
conformal dimension , while shadow -forms of this weight are only
pure gauge in the critical spacetime dimension value . We then provide
a systematic technique to obtain the large- asymptotic limit near based on the method of regions, which naturally takes into account the
presence of both ordinary and contact terms on the celestial sphere. In ,
this allows us to reformulate in a conformal primary language the links between
scalars and dual two-forms.Comment: 56 pages + reference
Horizon symmetries and hairy black holes in AdS
We investigate whether supertranslation symmetry may appear in a scenario that involves black holes in AdS space. The framework we consider is massive 3D gravity, which admits a rich black hole phase space, including stationary AdS black holes with softly decaying hair. We consider a set of asymptotic conditions that permits such decaying near the boundary, and which, in addition to the local conformal symmetry, is preserved by an extra local current. The corresponding algebra of diffeomorphisms consists of two copies of Virasoro algebra in semi-direct sum with an infinite-dimensional Abelian ideal. We then reorient the analysis to the near horizon region, where infinite-dimensional symmetries also appear. The supertranslation symmetry at the horizon yields an infinite set of non-trivial charges, which we explicitly compute. The zero-mode of these charges correctly reproduces the black hole entropy. In contrast to Einstein gravity, in the higher-derivative theory subleading terms in the near horizon expansion contribute to the near horizon charges. Such terms happen to capture the higher-curvature corrections to the Bekenstein area law.Fil: Donnay, Laura. Vienna University of Technology; AustriaFil: Giribet, Gaston Enrique. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de FĂsica de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FĂsica de Buenos Aires; ArgentinaFil: Oliva, Julio. Universidad de ConcepciĂłn; Chil
- …