13 research outputs found
Note on New Massive Gravity in
In this note we study the properties of linearized gravitational excitations
in the new massive gravity theory in asymptotically spacetime and find
that there is also a critical point for the mass parameter at which massive
gravitons become massless as in topological massive gravity in .
However, at this critical point in the new massive gravity the energy of all
branches of highest weight gravitons vanish and the central charges also vanish
within the Brown-Henneaux boundary conditions. The new massive gravity in
asymptotically spacetime seems to be trivial at this critical point
under the Brown-Henneaux boundary conditions if the Brown-Henneaux boundary
conditions can be consistent with this theory. At this point, the boundary
conditions of log gravity may be preferred.Comment: v3 typos corrected, refs added, version to appear in JHE
Chiral Gravity in Three Dimensions
Three dimensional Einstein gravity with negative cosmological constant
-1/\ell^2 deformed by a gravitational Chern-Simons action with coefficient
1/\mu is studied in an asymptotically AdS_3 spacetime. It is argued to violate
unitary or positivity for generic \mu due to negative-energy massive gravitons.
However at the critical value \mu\ell=1, the massive gravitons disappear and
BTZ black holes all have mass and angular momentum related by \ell M=J. The
corresponding chiral quantum theory of gravity is conjectured to exist and be
dual to a purely right-moving boundary CFT with central charges
(c_L,c_R)=(0,3\ell /G).Comment: 21 pages, published version, typos corrected, more reference adde
The Higher Spin/Vector Model Duality
This paper is mainly a review of the dualities between Vasiliev's higher spin
gauge theories in AdS4 and three dimensional large N vector models, with focus
on the holographic calculation of correlation functions of higher spin
currents. We also present some new results in the computation of parity odd
structures in the three point functions in parity violating Vasiliev theories.Comment: 55 pages, 1 figure. Contribution to J. Phys. A special volume on
"Higher Spin Theories and AdS/CFT" edited by M. R. Gaberdiel and M. Vasiliev.
v2: references adde
Extremal single-charge small black holes: Entropy function analysis
We study stretched horizons of the type AdS_2 x S^8 for certain spherically
symmetric extremal small black holes in type IIA carrying only D0-brane charge
making use of Sen's entropy function formalism for higher derivative gravity. A
scaling argument is given to show that the entropy of this class of black holes
for large charge behaves as \sqrt{|q|} where q is the electric charge. The
leading order result arises from IIA string loop corrections. We find that for
solutions to exist the force on a probe D0-brane has to vanish and we prove
that this feature persists to all higher derivative orders. We comment on the
nature of the extremum of these solutions and on the sub-leading corrections to
the entropy. The entropy of other small black holes related by dualities to our
case is also discussed.Comment: 19 pages, v2:typos corrected and references adde
Matrix Model and Time-like Linear Dilaton Matter
We consider a matrix model description of the 2d string theory whose matter
part is given by a time-like linear dilaton CFT. This is equivalent to the c=1
matrix model with a deformed, but very simple fermi surface. Indeed, after a
Lorentz transformation, the corresponding 2d spacetime is a conventional linear
dilaton background with a time-dependent tachyon field. We show that the tree
level scattering amplitudes in the matrix model perfectly agree with those
computed in the world-sheet theory. The classical trajectories of fermions
correspond to the decaying D-branes in the time-like linear dilaton CFT. We
also discuss the ground ring structure. Furthermore, we study the properties of
the time-like Liouville theory by applying this matrix model description. We
find that its ground ring structure is very similar to that of the minimal
string.Comment: 30 pages, harvmac, typos corrected, acknowledgements and comments
added(v2), published version (v3
Gravity duals for logarithmic conformal field theories
Logarithmic conformal field theories with vanishing central charge describe
systems with quenched disorder, percolation or dilute self-avoiding polymers.
In these theories the energy momentum tensor acquires a logarithmic partner. In
this talk we address the construction of possible gravity duals for these
logarithmic conformal field theories and present two viable candidates for such
duals, namely theories of massive gravity in three dimensions at a chiral
point.Comment: 15 pages, 1 figure, invited plenary talk at the First Mediterranean
Conference on Classical and Quantum Gravity, v2: published version, corrected
typo in left eq. (5
Black Holes as Effective Geometries
Gravitational entropy arises in string theory via coarse graining over an
underlying space of microstates. In this review we would like to address the
question of how the classical black hole geometry itself arises as an effective
or approximate description of a pure state, in a closed string theory, which
semiclassical observers are unable to distinguish from the "naive" geometry. In
cases with enough supersymmetry it has been possible to explicitly construct
these microstates in spacetime, and understand how coarse-graining of
non-singular, horizon-free objects can lead to an effective description as an
extremal black hole. We discuss how these results arise for examples in Type II
string theory on AdS_5 x S^5 and on AdS_3 x S^3 x T^4 that preserve 16 and 8
supercharges respectively. For such a picture of black holes as effective
geometries to extend to cases with finite horizon area the scale of quantum
effects in gravity would have to extend well beyond the vicinity of the
singularities in the effective theory. By studying examples in M-theory on
AdS_3 x S^2 x CY that preserve 4 supersymmetries we show how this can happen.Comment: Review based on lectures of JdB at CERN RTN Winter School and of VB
at PIMS Summer School. 68 pages. Added reference
Lectures on on Black Holes, Topological Strings and Quantum Attractors (2.0)
In these lecture notes, we review some recent developments on the relation
between the macroscopic entropy of four-dimensional BPS black holes and the
microscopic counting of states, beyond the thermodynamical, large charge limit.
After a brief overview of charged black holes in supergravity and string
theory, we give an extensive introduction to special and very special geometry,
attractor flows and topological string theory, including holomorphic anomalies.
We then expose the Ooguri-Strominger-Vafa (OSV) conjecture which relates
microscopic degeneracies to the topological string amplitude, and review
precision tests of this formula on ``small'' black holes. Finally, motivated by
a holographic interpretation of the OSV conjecture, we give a systematic
approach to the radial quantization of BPS black holes (i.e. quantum
attractors). This suggests the existence of a one-parameter generalization of
the topological string amplitude, and provides a general framework for
constructing automorphic partition functions for black hole degeneracies in
theories with sufficient degree of symmetry.Comment: 103 pages, 8 figures, 21 exercises, uses JHEP3.cls; v5: important
upgrade, prepared for the proceedings of Frascati School on Attractor
Mechanism; Sec 7 was largely rewritten to incorporate recent progress; more
figures, more refs, and minor changes in abstract and introductio