1,396 research outputs found
Strings on conifolds from strong coupling dynamics: quantitative results
Three quantitative features of string theory on AdS_5 x X_5, for any
(quasi)regular Sasaki-Einstein X_5, are recovered exactly from an expansion of
field theory at strong coupling around configurations in the moduli space of
vacua. These configurations can be thought of as a generalized matrix model of
(local) commuting matrices. First, we reproduce the spectrum of scalar
Kaluza-Klein modes on X_5. Secondly, we recover the precise spectrum of BMN
string states, including a nontrivial dependence on the volume of X_5. Finally,
we show how the radial direction in global AdS_5 emerges universally in these
theories by exhibiting states dual to AdS giant gravitons.Comment: 1+28 pages. 1 figur
Strings on conifolds from strong coupling dynamics, part I
A method to solve various aspects of the strong coupling expansion of the
superconformal field theory duals of AdS_5 x X geometries from first principles
is proposed. The main idea is that at strong coupling the configurations that
dominate the low energy dynamics of the field theory compactified on a three
sphere are given by certain non-trivial semi-classical configurations in the
moduli space of vacua.
We show that this approach is self-consistent and permits one to express most
of the dynamics in terms of an effective N=4 SYM dynamics. This has the
advantage that some degrees of freedom that move the configurations away from
moduli space can be treated perturbatively, unifying the essential low energy
dynamics of all of these theories. We show that with this formalism one can
compute the energies of strings in the BMN limit in the Klebanov-Witten theory
from field theory considerations, matching the functional form of results found
using AdS geometry. This paper also presents various other technical results
for the semiclassical treatment of superconformal field theories.Comment: 52 pages, JHEP3 styl
A strong coupling expansion for N=4 SYM theory and other SCFT's
Recent progress towards understanding a strong coupling expansion for various
superconformal field theories in four dimensions is described. First, the case
of the maximally supersymmetric Yang Mills theory is analyzed, as well as many
calculations that can be done directly at strong coupling and matched to the
AdS dual geometry. Also, this understanding is extended to other AdS duals
where the sphere is replaced by a Sasaki-Einstein manifold. Particular emphasis
is made on matching exactly part of the supergravity dual spectrum of various
of these field theories by using wave function methods.Comment: 10 pages, Contribution to the proceedings of the Osaka Workshop,
OCU200
Emergent geometry from q-deformations of N=4 super Yang-Mills
We study BPS states in a marginal deformation of super Yang-Mills on R x S^3
using a quantum mechanical system of q-commuting matrices. We focus mainly on
the case where the parameter q is a root of unity, so that the AdS dual of the
field theory can be associated to an orbifold of AdS_5x S^5. We show that in
the large N limit, BPS states are described by density distributions of
eigenvalues and we assign to these distributions a geometrical spacetime
interpretation. We go beyond BPS configurations by turning on perturbative
non-q-commuting excitations. Considering states in an appropriate BMN limit, we
use a saddle point approximation to compute the BMN energy to all perturbative
orders in the 't Hooft coupling. We also examine some BMN like states that
correspond to twisted sector string states in the orbifold and we show that our
geometrical interpretation of the system is consistent with the quantum numbers
of the corresponding states under the quantum symmetry of the orbifold.Comment: 22 pages, 1 figure. v2: added references. v3:final published versio
Black Hole Production from High Energy Scattering in AdS/CFT
In this article we show how to set up initial states in SYM
theory that correspond to high energy graviton collisions, leading to black
hole formation in . For this purpose, we study states in the
gauge theory that are dual to graviton wavepackets localized at the center of
, and carrying large angular momentum along the . These states are
created by exciting only the s-wave mode of one of the complex adjoint scalars
of SYM. For a single graviton, the state is 1/2 BPS and one can show that it is
dual to a linearized 1/2 BPS geometry in the bulk. Exploiting this dictionary,
we show how to localize the particle's wavefunciton so that the dual linearized
metric has the form of a Aichelburg-Sexl shock wave. One can then put two such
shock waves into a head-on collision, which is known to produce a trapped
surface. Finally, we discuss the prospect of studying graviton scattering
directly at strong coupling in the gauge theory using a reduced model of matrix
quantum mechanics.Comment: 11 pages, revtex format, no figure
Multi-matrix models and emergent geometry
Encouraged by the AdS/CFT correspondence, we study emergent local geometry in
large N multi-matrix models from the perspective of a strong coupling
expansion. By considering various solvable interacting models we show how the
emergence or non-emergence of local geometry at strong coupling is captured by
observables that effectively measure the mass of off-diagonal excitations about
a semiclassical eigenvalue background. We find emergent geometry at strong
coupling in models where a mass term regulates an infrared divergence. We also
show that our notion of emergent geometry can be usefully applied to fuzzy
spheres. Although most of our results are analytic, we have found numerical
input valuable in guiding and checking our results.Comment: 1+34 pages, 4 figures. References adde
A study of open strings ending on giant gravitons, spin chains and integrability
We systematically study the spectrum of open strings attached to half BPS
giant gravitons in the N=4 SYM AdS/CFT setup. We find that some null
trajectories along the giant graviton are actually null geodesics of AdS_5x
S^5, so that we can study the problem in a plane wave limit setup. We also find
the description of these states at weak 't Hooft coupling in the dual CFT. We
show how the dual description is given by an open spin chain with variable
number of sites. We analyze this system in detail and find numerical evidence
for integrability. We also discover an interesting instability of long open
strings in Ramond-Ramond backgrounds that is characterized by having a
continuum spectrum of the string, which is separated from the ground state by a
gap. This instability arises from accelerating the D-brane on which the strings
end via the Ramond-Ramond field. From the integrable spin chain point of view,
this instability prevents us from formulating the integrable structure in terms
of a Bethe Ansatz construction.Comment: 38 pages+appendices, 9 figures. Uses JHEP3. v2: added reference
Aspects of ABJM orbifolds with discrete torsion
We analyze orbifolds with discrete torsion of the ABJM theory by a finite
subgroup of . Discrete torsion is implemented by
twisting the crossed product algebra resulting after orbifolding. It is shown
that, in general, the order of the cocycle we chose to twist the algebra by
enters in a non trivial way in the moduli space. To be precise, the M-theory
fiber is multiplied by a factor of in addition to the other effects that
were found before in the literature. Therefore we got a
action on the fiber. We present a general
analysis on how this quotient arises along with a detailed analysis of the
cases where is abelian
A Monte-Carlo study of the AdS/CFT correspondence: an exploration of quantum gravity effects
In this paper we study the AdS/CFT correspondence for N=4 SYM with gauge
group U(N), compactified on S^3 in four dimensions using Monte-Carlo
techniques. The simulation is based on a particular reduction of degrees of
freedom to commuting matrices of constant fields, and in particular, we can
write the wave functions of these degrees of freedom exactly. The square of the
wave function is equivalent to a probability density for a Boltzman gas of
interacting particles in six dimensions. From the simulation we can extract the
density particle distribution for each wave function, and this distribution can
be interpreted as a special geometric locus in the gravitational dual. Studying
the wave functions associated to half-BPS giant gravitons, we are able to show
that the matrix model can measure the Planck scale directly. We also show that
the output of our simulation seems to match various theoretical expectations in
the large N limit and that it captures 1/N effects as statistical fluctuations
of the Boltzman gas with the expected scaling. Our results suggest that this is
a very promising approach to explore quantum corrections and effects in
gravitational physics on AdS spaces.Comment: 40 pages, 7 figures, uses JHEP. v2: references adde
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