215 research outputs found
Superconductors from Superstrings
We establish that in a large class of strongly coupled 3+1 dimensional N=1
quiver conformal field theories with gravity duals, adding a chemical potential
for the R-charge leads to the existence of superfluid states in which a chiral
primary operator of the schematic form O = \lambda\lambda + W condenses. Here
\lambda is a gluino and W is the superpotential. Our argument is based on the
construction of a consistent truncation of type IIB supergravity that includes
a U(1) gauge field and a complex scalar.Comment: 5 pages, 2 figures; v2 improved figure, small change
Exceptional Collections and del Pezzo Gauge Theories
Stacks of D3-branes placed at the tip of a cone over a del Pezzo surface
provide a way of geometrically engineering a small but rich class of
gauge/gravity dualities. We develop tools for understanding the resulting
quiver gauge theories using exceptional collections. We prove two important
results for a general quiver gauge theory: 1) we show the ordering of the nodes
can be determined up to cyclic permutation and 2) we derive a simple formula
for the ranks of the gauge groups (at the conformal point) in terms of the
numbers of bifundamentals. We also provide a detailed analysis of four node
quivers, examining when precisely mutations of the exceptional collection are
related to Seiberg duality.Comment: 26 pages, 1 figure; v2 footnote 2 amended; v3 ref adde
The Second Sound of SU(2)
Using the AdS/CFT correspondence, we calculate the transport coefficients of
a strongly interacting system with a non-abelian SU(2) global symmetry near a
second order phase transition. From the behavior of the poles in the Green's
functions near the phase transition, we determine analytically the speed of
second sound, the conductivity, and diffusion constants. We discuss
similarities and differences between this and other systems with vector order
parameters such as p-wave superconductors and liquid helium-3.Comment: 31 pages, 2 figures; v2 ref added, typo fixe
Quantum critical transport, duality, and M-theory
We consider charge transport properties of 2+1 dimensional conformal field
theories at non-zero temperature. For theories with only Abelian U(1) charges,
we describe the action of particle-vortex duality on the
hydrodynamic-to-collisionless crossover function: this leads to powerful
functional constraints for self-dual theories. For the n=8 supersymmetric,
SU(N) Yang-Mills theory at the conformal fixed point, exact
hydrodynamic-to-collisionless crossover functions of the SO(8) R-currents can
be obtained in the large N limit by applying the AdS/CFT correspondence to
M-theory. In the gravity theory, fluctuating currents are mapped to fluctuating
gauge fields in the background of a black hole in 3+1 dimensional anti-de
Sitter space. The electromagnetic self-duality of the 3+1 dimensional theory
implies that the correlators of the R-currents obey a functional constraint
similar to that found from particle-vortex duality in 2+1 dimensional Abelian
theories. Thus the 2+1 dimensional, superconformal Yang Mills theory obeys a
"holographic self duality" in the large N limit, and perhaps more generally.Comment: 35 pages, 4 figures; (v2) New appendix on CFT2, corrected
normalization of gauge field action, added ref
Operator Counting and Eigenvalue Distributions for 3D Supersymmetric Gauge Theories
We give further support for our conjecture relating eigenvalue distributions
of the Kapustin-Willett-Yaakov matrix model in the large N limit to numbers of
operators in the chiral ring of the corresponding supersymmetric
three-dimensional gauge theory. We show that the relation holds for
non-critical R-charges and for examples with {\mathcal N}=2 instead of
{\mathcal N}=3 supersymmetry where the bifundamental matter fields are
nonchiral. We prove that, for non-critical R-charges, the conjecture is
equivalent to a relation between the free energy of the gauge theory on a three
sphere and the volume of a Sasaki manifold that is part of the moduli space of
the gauge theory. We also investigate the consequences of our conjecture for
chiral theories where the matrix model is not well understood.Comment: 27 pages + appendices, 5 figure
Seiberg Duality is an Exceptional Mutation
The low energy gauge theory living on D-branes probing a del Pezzo
singularity of a non-compact Calabi-Yau manifold is not unique. In fact there
is a large equivalence class of such gauge theories related by Seiberg duality.
As a step toward characterizing this class, we show that Seiberg duality can be
defined consistently as an admissible mutation of a strongly exceptional
collection of coherent sheaves.Comment: 32 pages, 4 figures; v2 refs added, "orbifold point" discussion
refined; v3 version to appear in JHEP, discussion of torsion sheaves improve
Energy Loss of Heavy Quarks from Asymptotically AdS Geometries
We investigate some universal features of AdS/CFT models of heavy quark
energy loss. In addition, as a specific example, we examine quark damping in
the spinning D3-brane solution dual to N=4 SU(N_c) super Yang-Mills at finite
temperature and R-charge chemical potential.Comment: 17 pages, 9 figures; v2 refs added, typo fixe
Supersymmetry Breaking from a Calabi-Yau Singularity
We conjecture a geometric criterion for determining whether supersymmetry is
spontaneously broken in certain string backgrounds. These backgrounds contain
wrapped branes at Calabi-Yau singularites with obstructions to deformation of
the complex structure. We motivate our conjecture with a particular example:
the quiver gauge theory corresponding to a cone over the first del
Pezzo surface, . This setup can be analyzed using ordinary supersymmetric
field theory methods, where we find that gaugino condensation drives a
deformation of the chiral ring which has no solutions. We expect this breaking
to be a general feature of any theory of branes at a singularity with a smaller
number of possible deformations than independent anomaly-free fractional
branes.Comment: 32 pages, 6 figures, latex, v2: minor changes, refs adde
String Tensions and Three Dimensional Confining Gauge Theories
In the context of gauge/gravity duality, we try to understand better the
proposed duality between the fractional D2-brane supergravity solutions of
(Nucl. Phys. B 606 (2001) 18, hep-th/0101096) and a confining 2+1 dimensional
gauge theory. Based on the similarities between this fractional D2-brane
solution and D3-brane supergravity solutions with more firmly established gauge
theory duals, we conjecture that a confining q-string in the 2+1 dimensional
gauge theory is dual to a wrapped D4-brane. In particular, the D4-brane looks
like a string in the gauge theory directions but wraps a S**3 in S**4 in the
transverse geometry. For one of the supergravity solutions, we find a near
quadratic scaling law for the tension: . Based on the tension,
we conjecture that the gauge theory dual is SU(N) far in the infrared. We also
conjecture that a quadratic or near quadratic scaling is a generic feature of
confining 2+1 dimensional SU(N) gauge theories.Comment: 23 pages, 2 figure
Brane Tilings and Exceptional Collections
Both brane tilings and exceptional collections are useful tools for
describing the low energy gauge theory on a stack of D3-branes probing a
Calabi-Yau singularity. We provide a dictionary that translates between these
two heretofore unconnected languages. Given a brane tiling, we compute an
exceptional collection of line bundles associated to the base of the
non-compact Calabi-Yau threefold. Given an exceptional collection, we derive
the periodic quiver of the gauge theory which is the graph theoretic dual of
the brane tiling. Our results give new insight to the construction of quiver
theories and their relation to geometry.Comment: 46 pages, 37 figures, JHEP3; v2: reference added, figure 13 correcte
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