98 research outputs found
Fermions from Half-BPS Supergravity
We discuss collective coordinate quantization of the half-BPS geometries of
Lin, Lunin and Maldacena (hep-th/0409174). The LLM geometries are parameterized
by a single function on a plane. We treat this function as a collective
coordinate. We arrive at the collective coordinate action as well as path
integral measure by considering D3 branes in an arbitrary LLM geometry. The
resulting functional integral is shown, using known methods (hep-th/9309028),
to be the classical limit of a functional integral for free fermions in a
harmonic oscillator. The function gets identified with the classical limit
of the Wigner phase space distribution of the fermion theory which satisfies u
* u = u. The calculation shows how configuration space of supergravity becomes
a phase space (hence noncommutative) in the half-BPS sector. Our method sheds
new light on counting supersymmetric configurations in supergravity.Comment: 28 pages, 2 figures, epsf;(v3) eq. (3.3) clarified and notationally
simplified; version to appear in JHE
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
Matrix dynamics of fuzzy spheres
We study the dynamics of fuzzy two-spheres in a matrix model which represents
string theory in the presence of RR flux. We analyze the stability of known
static solutions of such a theory which contain commuting matrices and SU(2)
representations. We find that irreducible as well as reducible representations
are stable. Since the latter are of higher energy, this stability poses a
puzzle. We resolve this puzzle by noting that reducible representations have
marginal directions corresponding to non-spherical deformations. We obtain new
static solutions by turning on these marginal deformations. These solutions now
have instability or tachyonic directions. We discuss condensation of these
tachyons which correspond to classical trajectories interpolating from
multiple, small fuzzy spheres to a single, large sphere. We briefly discuss
spatially independent configurations of a D3/D5 system described by the same
matrix model which now possesses a supergravity dual.Comment: 26 pages, 3 figures, uses JHEP.cls; (v2) references adde
Rational foundation of GR in terms of statistical mechanic in the AdS/CFT framework
In this article, we work out the microscopic statistical foundation of the
supergravity description of the simplest 1/2 BPS sector in the AdS(5)/CFT(4).
Then, all the corresponding supergravity observables are related to
thermodynamical observables, and General Relativity is understood as a
mean-field theory. In particular, and as an example, the Superstar is studied
and its thermodynamical properties clarified.Comment: 13 pages, 6 eps figures, latex, some improvements introduced,
reference added, typos correcte
On the existence of supergravity duals to D1--D5 CFT states
We define a metric operator in the 1/2-BPS sector of the D1-D5 CFT, the
eigenstates of which have a good semi-classical supergravity dual; the
non-eigenstates cannot be mapped to semi-classical gravity duals. We also
analyse how the data defining a CFT state manifests itself in the gravity side,
and show that it is arranged into a set of multipoles. Interestingly, we find
that quantum mechanical interference in the CFT can have observable
manifestations in the semi-classical gravity dual. We also point out that the
multipoles associated to the normal statistical ensemble fluctuate wildly,
indicating that the mixed thermal state should not be associated to a
semi-classical geometry.Comment: 22 pages, 2 figures. v2 : references added, typos correcte
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
D0 Matrix Mechanics: New Fuzzy Solutions at Large N
We wish to consider in this report the large N limit of a particular matrix
model introduced by Myers describing D-brane physics in the presence of an RR
flux background. At finite N, fuzzy spheres appear naturally as non-trivial
solutions to this matrix model and have been extensively studied. In this
report, we wish to demonstrate several new classes of solutions which appear in
the large N limit, corresponding to the fuzzy cylinder,the fuzzy plane and a
warped fuzzy plane. The latter two solutions arise from a possible "central
extension" to our model that arises after we account for non-trivial issues
involved in the large N limit. As is the case for finite N, these new solutions
are to be interpreted as constituent D0-branes forming D2 bound states
describing new fuzzy geometries.Comment: revised version: references added, derivation of "central extensions"
improved upon. To appear in JHE
On the Classical String Solutions and String/Field Theory Duality
We classify almost all classical string configurations, considered in the
framework of the semi-classical limit of the string/gauge theory duality. Then,
we describe a procedure for obtaining the conserved quantities and the exact
classical string solutions in general string theory backgrounds, when the
string embedding coordinates depend non-linearly on the worldsheet time
parameter.Comment: LaTeX, 15 pages, no figures; V2: some typos corrected; V3: no
corrections, to appear in JHE
Semi-classical Probe Strings on Giant Gravitons Backgrounds
In the first part of this paper we study two symmetries of the LLM
metric, both of which exchange black and white regions. One of them which can
be interpreted as the particle-hole symmetry is the symmetry of the whole
supergravity solution while the second one is just the symmetry of the metric
and changes the sign of the fivefrom flux. In the second part of the paper we
use closed string probes and their semi-classical analysis to compare the two
1/2 BPS deformations of , the smooth LLM geometry which
contains localized giant gravitons and the superstar case which is a solution
with naked singularity corresponding to smeared giants. We discuss the
realization of the symmetry in the semi-classical closed string probes
point of view.Comment: 29 pages, 6 .eps figures; v2: References adde
Extended Fermion Representation of Multi-Charge 1/2-BPS Operators in AdS/CFT -- Towards Field Theory of D-Branes --
We extend the fermion representation of single-charge 1/2-BPS operators in
the four-dimensional N=4 super Yang-Mills theory to general (multi-charge)
1/2-BPS operators such that all six directions of scalar fields play roles on
an equal footing. This enables us to construct a field-theorectic
representation for a second-quantized system of spherical D3-branes in the
1/2-BPS sector. The Fock space of D3-branes is characterized by a novel
exclusion principle (called `Dexclusion' principle), and also by a nonlocality
which is consistent with the spacetime uncertainty relation. The Dexclusion
principle is realized by composites of two operators, obeying the usual
canonical anticommutation relation and the Cuntz algebra, respectively. The
nonlocality appears as a consequence of a superselction rule associated with a
symmetry which is related to the scale invariance of the super Yang-Mills
theory. The entropy of the so-called superstars, with multiple charges, which
have been proposed to be geometries corresponding to the condensation of giant
gravitons is discussed from our viewpoint and is argued to be consistent with
the Dexclusion principle. Our construction may be regarded as a first step
towards a possible new framework of general D-brane field theory.Comment: 43 pages, 4 figures; version 2, corrected typos and added reference
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