109 research outputs found
Do supersymmetric anti-de Sitter black rings exist?
We determine the most general near-horizon geometry of a supersymmetric,
asymptotically anti-de Sitter, black hole solution of five-dimensional minimal
gauged supergravity that admits two rotational symmetries. The near-horizon
geometry is that of the supersymmetric, topologically spherical, black hole
solution of Chong et al. This proves that regular supersymmetric anti-de Sitter
black rings with two rotational symmetries do not exist in minimal
supergravity. However, we do find a solution corresponding to the near-horizon
geometry of a supersymmetric black ring held in equilibrium by a conical
singularity, which suggests that nonsupersymmetric anti-de Sitter black rings
may exist but cannot be "balanced" in the supersymmetric limit.Comment: Latex, 18 pages, 1 figure. v2: minor change
Phase transitions and statistical mechanics for BPS Black Holes in AdS/CFT
Using the general framework developed in hep-th/0607056, we study in detail
the phase space of BPS Black Holes in AdS, for the case where all three
electric charges are equal. Although these solitons are supersymmetric with
zero Hawking temperature, it turns out that these Black Holes have rich phase
structure with sharp phase transitions associated to a corresponding critical
generalized temperature. We are able to rewrite the gravity variables in terms
of dual CFT variables and compare the gravity phase diagram with the free dual
CFT phase diagram. In particular, the elusive supergravity constraint
characteristic of these Black Holes is particulary simple and in fact appears
naturally in the dual CFT in the definition of the BPS Index. Armed with this
constraint, we find perfect match between BH and free CFT charges up to
expected constant factors.Comment: 14 pages, 5 figures, corrected typos and references adde
A Fermi Surface Model for Large Supersymmetric AdS_5 Black Holes
We identify a large family of 1/16 BPS operators in N=4 SYM that
qualitatively reproduce the relations between charge, angular momentum and
entropy in regular supersymmetric AdS_5 black holes when the main contribution
to their masses is given by their angular momentum.Comment: 32 pages, 6 figures, LaTeX uses JHEP3 class; ver 2- added
acknowledgment, minor change
On a class of 4D Kahler bases and AdS_5 supersymmetric Black Holes
We construct a class of toric Kahler manifolds, M_4, of real dimension four,
a subset of which corresponds to the Kahler bases of all known 5D
asymptotically AdS_5 supersymmetric black-holes. In a certain limit, these
Kahler spaces take the form of cones over Sasaki spaces, which, in turn, are
fibrations over toric manifolds of real dimension two. The metric on M_4 is
completely determined by a single function H(x), which is the conformal factor
of the two dimensional space. We study the solutions of minimal five
dimensional gauged supergravity having this class of Kahler spaces as base and
show that in order to generate a five dimensional solution H(x) must obey a
simple sixth order differential equation. We discuss the solutions in detail,
which include all known asymptotically AdS_5 black holes as well as other
spacetimes with non-compact horizons. Moreover we find an infinite number of
supersymmetric deformations of these spacetimes with less spatial isometries
than the base space. These deformations vanish at the horizon, but become
relevant asymptotically.Comment: 34 pages, 3 figures. v2: formula (8.35) and other minor typos
corrected; references added; accepted for publication in JHE
Dual giant gravitons in AdS Y (Sasaki-Einstein)
We consider BPS motion of dual giant gravitons on Ad where
represents a five-dimensional Sasaki-Einstein manifold. We find that the
phase space for the BPS dual giant gravitons is symplectically isomorphic to
the Calabi-Yau cone over , with the K\"{a}hler form identified with the
symplectic form. The quantization of the dual giants therefore coincides with
the K\"{a}hler quantization of the cone which leads to an explicit
correspondence between holomorphic wavefunctions of dual giants and
gauge-invariant operators of the boundary theory. We extend the discussion to
dual giants in where is a seven-dimensional
Sasaki-Einstein manifold; for special motions the phase space of the dual
giants is symplectically isomorphic to the eight-dimensional Calabi-Yau cone.Comment: 14 pages. (v2) typo's corrected; factors of AdS radius reinstated for
clarity; remarks about dual giant wavefunctions in T^{1,1} expanded and put
in a new subsectio
Counting 1/8-BPS Dual-Giants
We count 1/8-BPS states in type IIB string theory on AdS_5 x S^5 background
which carry three independent angular momenta on S^5. These states can be
counted by considering configurations of multiple dual-giant gravitons up to N
in number which share at least four supersymmetries. We map this counting
problem to that of counting the energy eigen states of a system of N bosons in
a 3-dimensional harmonic oscillator. We also count 1/8-BPS states with two
independent non-zero spins in AdS_5 and one non-zero angular momentum on S^5 by
considering configurations of arbitrary number of giant gravitons that share at
least four supersymmetries.Comment: 19 page
1/16-BPS Black Holes and Giant Gravitons in the AdS_5 X S^5 Space
We explore 1/16-BPS objects of type IIB string theory in AdS_5 * S^5. First,
we consider supersymmetric AdS_5 black holes, which should be 1/16-BPS and have
a characteristic that not all physical charges are independent. We point out
that the Bekenstein-Hawking entropy of these black holes admits a remarkably
simple expression in terms of (dependent) physical charges, which suggests its
microscopic origin via certain Cardy or Hardy-Ramanujan formula. We also note
that there is an upper bound for the angular momenta given by the electric
charges. Second, we construct a class of 1/16-BPS giant graviton solutions in
AdS_5 * S^5 and explore their properties. The solutions are given by the
intersections of AdS_5 * S^5 and complex 3 dimensional holomorphic hyperspaces
in C^{1+5}, the latter being the zero loci of three holomorphic functions which
are homogeneous with suitable weights on coordinates. We investigate examples
of giant gravitons, including their degenerations to tensionless strings.Comment: 25 pages, no figures, v2: references added, comments added in the
conclusio
Statistical mechanics of transcription-factor binding site discovery using Hidden Markov Models
Hidden Markov Models (HMMs) are a commonly used tool for inference of
transcription factor (TF) binding sites from DNA sequence data. We exploit the
mathematical equivalence between HMMs for TF binding and the "inverse"
statistical mechanics of hard rods in a one-dimensional disordered potential to
investigate learning in HMMs. We derive analytic expressions for the Fisher
information, a commonly employed measure of confidence in learned parameters,
in the biologically relevant limit where the density of binding sites is low.
We then use techniques from statistical mechanics to derive a scaling principle
relating the specificity (binding energy) of a TF to the minimum amount of
training data necessary to learn it.Comment: 25 pages, 2 figures, 1 table V2 - typos fixed and new references
adde
At the horizon of a supersymmetric AdS_5 black hole: Isometries and half-BPS giants
The near-horizon geometry of an asymptotically AdS_5 supersymmetric black
hole discovered by Gutowski and Reall is analysed. After lifting the solution
to 10 dimensions, we explicitly solve the Killing spinor equations in both
Poincare and global coordinates. It is found that exactly four supersymmetries
are preserved which is twice the number for the full black hole. The full set
of isometries is constructed and the isometry supergroup is shown to be
SU(1,1|1) X SU(2) X U(3). We further study half-BPS configurations of D3-branes
in the near-horizon geometry in Poincare and global coordinates. Both giant
graviton probes and dual giant graviton probes are found.Comment: 26 pages. v2:Typos corrected, minor change
Entropy function and attractors for AdS black holes
We apply Sen's entropy formalism to the study of the near horizon geometry
and the entropy of asymptotically AdS black holes in gauged supergravities. In
particular, we consider non-supersymmetric electrically charged black holes
with AdS_2 xS^{d-2} horizons in U(1)^4 and U(1)^3 gauged supergravities in d=4
and d=5 dimensions, respectively. We study several cases including
static/rotating, BPS and non-BPS black holes in Einstein as well as in
Gauss-Bonnet gravity. In all examples, the near horizon geometry and black hole
entropy are derived by extremizing the entropy function and are given entirely
in terms of the gauge coupling, the electric charges and the angular momentum
of the black hole.Comment: 27 pages, no figures, references adde
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