802 research outputs found
A review of the D1/D5 system and five dimensional black hole from supergravity and brane viewpoint
We review some aspects of the D1/D5 system of type IIB string theory and the
associated five dimensional black hole. We include a pedagogical discussion of
the construction of relevant classical solutions in supergravity. We discuss
the gauge theory and the conformal field theory relevant to D-brane description
of these systems. In order to discuss Hawking radiation we are automatically
led to a discussion of near-horizon geometries and their relation to gauge
theories and conformal field theories. We show how inputs from AdS/CFT
correspondence resolve some earlier puzzles regarding Hawking radiation.
Besides the D1/D5 system, we include a brief discussion of some
nonsupersymmetric systems which show unexpected agreement between supergravity
and perturbative brane/string computations. We also comment briefly on possible
implications of the AdS/CFT relation for the correspondence principle and for
the principle of black hole complementarity.Comment: 54 pages, Expanded version of ICTP Spring School lectures 1999; (v2)
references and 1 more "obedient non-susy" example adde
Quantum quench in matrix models: Dynamical phase transitions, Selective equilibration and the Generalized Gibbs Ensemble
Quantum quench dynamics is considered in a one dimensional unitary matrix
model with a single trace potential. This model is integrable and has been
studied in the context of non-critical string theory. We find dynamical phase
transitions, and study the role of the quantum critical point. In course of the
time evolutions, we find evidence of selective equilibration for a certain
class of observables. The equilibrium is governed by the Generalized Gibbs
Ensemble (GGE) and differs from the standard Gibbs ensemble. We compute the
production of entropy which is O(N) for large N matrices. An important feature
of the equilibration is the appearance of an energy cascade, reminiscent of the
Richardson cascade in turbulence, where we find flow of energy from initial
long wavelength modes to progressively shorter wavelength excitations. We
discuss possible implication of the equilibration and of GGE in string theories
and higher spin theories. In another related study, we compute time evolutions
in a double trace unitary matrix model, which arises as an effective theory of
D2 branes in IIA string theory in the confinement phase. We find similar
equilibrations and dynamical transitions in this matrix model. The dynamical
transitions are related to Gregory-Laflamme transitions in string theory and
are potentially connected with the issue of appearance of naked singularities.Comment: 46 pages, 28 figures; v2: minor corrections, references added;
related movies are on
http://www2.yukawa.kyoto-u.ac.jp/~mtakeshi/MQM/index.htm
What is the gravity dual of the confinement/deconfinement transition in holographic QCD?
We study the gravity dual of four dimensional pure Yang-Mills theory through
D4 branes, as proposed by Witten (holographic QCD). In this holographic QCD, it
has been widely believed that the confinement phase in the pure Yang-Mills
theory corresponds to the AdS D4 soliton in gravity and the deconfinement phase
corresponds to the black D4 brane. We inspect this conjecture carefully and
show that the correspondence between the black D4 brane and the deconfinement
phase is not correct. Instead, by using a slightly different set up, we find an
alternative gravity solution called "localized soliton", which would be
properly related to the deconfinement phase. In this case, the
confinement/deconfinement transition is realized as a Gregory-Laflamme type
transition. We find that our proposal naturally explains several known
properties of QCD.Comment: 6 pages, 1 figure, based on the proceedings of the Seventh
International Conference `Quantum Theory and Symmetries', held in Prague 2011
and XVII European Workshop on String Theory 2011, held in Padua; v2: minor
correction
Nonrenormalization of Mass of Some Nonsupersymmetric String States
It is argued that the quantum correction to the mass of some very massive,
nonsupersymmetric states vanishes in inverse proportion to their tree-level
mass to all orders in string loops. This approximate nonrenormalization can
explain the agreement between the perturbative degeneracy of these states and
the Sen entropy of the associated black holes.Comment: Additional details provided, in particular, of the analytic
continuation of the two point function. Discussion of higher loops
substantially amplified. References added, conclusions unchanged; 19 pages,
harvma
Supersymmetric Giant Graviton Solutions in AdS_3
We parameterize all classical probe brane configurations that preserve 4
supersymmetries in (a) the extremal D1-D5 geometry, (b) the extremal D1-D5-P
geometry, (c) the smooth D1-D5 solutions proposed by Lunin and Mathur and (d)
global . These configurations consist of D1
branes, D5 branes and bound states of D5 and D1 branes with the property that a
particular Killing vector is tangent to the brane worldvolume at each point. We
show that the supersymmetric sector of the D5 brane worldvolume theory may be
analyzed in an effective 1+1 dimensional framework that places it on the same
footing as D1 branes. In global AdS and the corresponding Lunin-Mathur
solution, the solutions we describe are `bound' to the center of AdS for
generic parameters and cannot escape to infinity. We show that these probes
only exist on the submanifold of moduli space where the background
field and theta angle vanish. We quantize these probes in the near horizon
region of the extremal D1-D5 geometry and obtain the theory of long strings
discussed by Seiberg and Witten.Comment: 63 page
Bosonization of non-relativistic fermions on a circle: Tomonaga's problem revisited
We use the recently developed tools for an exact bosonization of a finite
number of non-relativistic fermions to discuss the classic Tomonaga
problem. In the case of noninteracting fermions, the bosonized hamiltonian
naturally splits into an O piece and an O piece. We show that in the
large-N and low-energy limit, the O piece in the hamiltonian describes a
massless relativistic boson, while the O piece gives rise to cubic
self-interactions of the boson. At finite and high energies, the low-energy
effective description breaks down and the exact bosonized hamiltonian must be
used. We also comment on the connection between the Tomonaga problem and pure
Yang-Mills theory on a cylinder. In the dual context of baby universes and
multiple black holes in string theory, we point out that the O piece in
our bosonized hamiltonian provides a simple understanding of the origin of two
different kinds of nonperturbative O corrections to the black hole
partition function.Comment: latex, 28 pages, 5 epsf figure
The inside outs of AdS(3)/CFT(2): Exact AdS wormholes with entangled CFT duals
We present the complete family of solutions of 3D gravity (Lambda<0) with two
asymptotically AdS exterior regions. The solutions are constructed from data at
the two boundaries, which correspond to two independent and arbitrary stress
tensors T_R, \bar T_R, and T_L, \bar T_L. The two exteriors are smoothly joined
on to an interior region through a regular horizon. We find CFT duals of these
geometries which are entangled states of two CFT's. We compute correlators
between general operators at the two boundaries and find perfect agreement
between CFT and bulk calculations. We calculate and match the CFT entanglement
entropy (EE) with the holographic EE which involves geodesics passing through
the wormhole. We also compute a holographic, non-equilibrium entropy for the
CFT using properties of the regular horizon. The construction of the bulk
solutions here uses an exact version of Brown-Henneaux type diffeomorphisms
which are asymptotically nontrivial and transform the CFT states by two
independent unitary operators on the two sides. Our solutions provide an
infinite family of explicit examples of the ER=EPR relation of Maldacena and
Susskind [arXiv:1306.0533].Comment: 27 pages + 10 pages of Appendix and references; (v2) title changed
for clarity, typos fixed, references adde
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