14 research outputs found
Centrally extended symmetry algebra of asymptotically Goedel spacetimes
We define an asymptotic symmetry algebra for three-dimensional Goedel
spacetimes supported by a gauge field which turns out to be the semi-direct sum
of the diffeomorphisms on the circle with two loop algebras. A class of fields
admitting this asymptotic symmetry algebra and leading to well-defined
conserved charges is found. The covariant Poisson bracket of the conserved
charges is then shown to be centrally extended to the semi-direct sum of a
Virasoro algebra and two affine algebras.Comment: 12 pages, sign mistake corrected in the central charge, takes
precedence over published versio
Noncommutative Locally Anti-de Sitter Black Holes
We give a review of our joint work on strict deformation of BHTZ 2+1 black
holes \cite{BRS02,BDHRS03}. However some results presented here are not
published elsewhere, and an effort is made for enlightening the instrinsical
aspect of the constructions. This shows in particular that the three
dimensional case treated here could be generalized to an anti-de Sitter space
of arbitrary dimension provided one disposes of a universal deformation formula
for the actions of a parabolic subgroup of its isometry group.Comment: 10 pages, based on a talk given by P.B., to appear in the proceedings
of the workshop `Noncommutative Geometry and Physics 2004' (Feb. 2004, Keio
University, Japan) (World Scientific
TsT, and black strings
We study the relationship between TsT transformations, marginal deformations
of string theory on AdS backgrounds, and irrelevant deformations of 2d
CFTs. We show that TsT transformations of NS-NS backgrounds correspond to
instantaneous deformations of the worldsheet action by the antisymmetric
product of two Noether currents, holographically mirroring the definition of
the , , , and deformations of 2d CFTs.
Applying a TsT transformation to string theory on BTZ we
obtain a general class of rotating black string solutions, including the
Horne-Horowitz and the Giveon-Itzhaki-Kutasov ones as special cases, which we
show are holographically dual to thermal states in single-trace
-deformed CFTs. We also find a smooth solution interpolating between
global AdS in the IR and a linear dilaton background in the UV that is
interpreted as the NS-NS ground state in the dual -deformed CFT. This
background suggests the existence of an upper bound on the deformation
parameter above which the solution becomes complex. We find that the worldsheet
spectrum, the thermodynamics of the black strings (in particular their
Bekenstein-Hawking entropy), and the critical value of the deformation
parameter match the corresponding quantities obtained from single-trace
deformations.Comment: 50 pages; v2: added references, corrected typos, and made minor
improvements, matches published versio
Soft Heisenberg hair on black holes in three dimensions
Three-dimensional Einstein gravity with negative cosmological constant admits
stationary black holes that are not necessarily spherically symmetric. We
propose boundary conditions for the near horizon region of these black holes
that lead to a surprisingly simple near horizon symmetry algebra consisting of
two affine u(1) current algebras. The symmetry algebra is essentially
equivalent to the Heisenberg algebra. The associated charges give a specific
example of "soft hair" on the horizon, as defined by Hawking, Perry and
Strominger. We show that soft hair does not contribute to the
Bekenstein-Hawking entropy of Banados-Teitelboim-Zanelli black holes and "black
flower" generalizations. From the near horizon perspective the conformal
generators at asymptotic infinity appear as composite operators, which we
interpret in the spirit of black hole complementarity. Another remarkable
feature of our boundary conditions is that they are singled out by requiring
that the whole spectrum is compatible with regularity at the horizon,
regardless the value of the global charges like mass or angular momentum.
Finally, we address black hole microstates and generalizations to cosmological
horizons.Comment: 6p
Holographic entanglement entropy and gravitational anomalies
We study entanglement entropy in two-dimensional conformal field theories with a gravitational anomaly. In theories with gravity duals, this anomaly is holographically represented by a gravitational Chern-Simons term in the bulk action. We show that the anomaly broadens the Ryu-Takayanagi minimal worldline into a ribbon, and that the anomalous contribution to the CFT entanglement entropy is given by the twist in this ribbon. The entanglement functional may also be interpreted as the worldline action for a spinning particle — that is, an anyon — in three-dimensional curved spacetime. We demonstrate that the minimization of this action results in the Mathisson-Papapetrou-Dixon equations of motion for a spinning particle in three dimensions. We work out several simple examples and demonstrate agreement with CFT calculations
Cosmic Evolution from Phase Transition of Three-Dimensional Flat Space
Flat space cosmology spacetimes are exact time-dependent solutions of three-dimensional gravity theories, such as Einstein gravity or topologically massive gravity. We exhibit a novel kind of phase transition between these cosmological spacetimes and the Minkowski vacuum. At sufficiently high temperature, (rotating) hot flat space tunnels into a universe described by flat space cosmology