132 research outputs found
Singularity Resolution in Gauged Supergravity and Conifold Unification
We obtain a unified picture for the conifold singularity resolution. We
propose that gauged supergravity, through a novel prescription for the
twisting, provides an appropriate framework to smooth out singularities in the
context of gravity duals of supersymmetric gauge theories.Comment: 13 pages, harvmac, one figure; v2: reference adde
Let's Twist Again: General Metrics of G(2) Holonomy from Gauged Supergravity
We construct all complete metrics of cohomogeneity one G(2) holonomy with S^3
x S^3 principal orbits from gauged supergravity. Our approach rests on a
generalization of the twisting procedure used in this framework. It corresponds
to a non-trivial embedding of the special Lagrangian three-cycle wrapped by the
D6-branes in the lower dimensional supergravity. There are constraints that
neatly reduce the general ansatz to a six functions one. Within this approach,
the Hitchin system and the flop transformation are nicely realized in eight
dimensional gauged supergravity.Comment: 31 pages, latex; v2: minor changes, references adde
Prepotential and Instanton Corrections in N=2 Supersymmetric SU(N_1)xSU(N_2) Yang Mills Theories
In this paper we analyse the non-hyperelliptic Seiberg-Witten curves derived
from M-theory that encode the low energy solution of N=2 supersymmetric
theories with product gauge groups. We consider the case of a SU(N_1)xSU(N_2)
gauge theory with a hypermultiplet in the bifundamental representation together
with matter in the fundamental representations of SU(N_1) and SU(N_2). By means
of the Riemann bilinear relations that hold on the Riemann surface defined by
the Seiberg--Witten curve, we compute the logarithmic derivative of the
prepotential with respect to the quantum scales of both gauge groups. As an
application we develop a method to compute recursively the instanton
corrections to the prepotential in a straightforward way. We present explicit
formulas for up to third order on both quantum scales. Furthermore, we extend
those results to SU(N) gauge theories with a matter hypermultiplet in the
symmetric and antisymmetric representation. We also present some non-trivial
checks of our results.Comment: 21 pages, 2 figures, minor changes and references adde
Wrapped branes with fluxes in 8d gauged supergravity
We study the gravity dual of several wrapped D-brane configurations in
presence of 4-form RR fluxes partially piercing the unwrapped directions. We
present a systematic approach to obtain these solutions from those without
fluxes. We use D=8 gauged supergravity as a starting point to build up these
solutions. The configurations include (smeared) M2-branes at the tip of a G_2
cone on S^3 x S^3, D2-D6 branes with the latter wrapping a special Lagrangian
3-cycle of the complex deformed conifold and an holomorphic sphere in its
cotangent bundle T^*S^2, D3-branes at the tip of the generalized resolved
conifold, and others obtained by means of T duality and KK reduction. We
elaborate on the corresponding N=1 and N=2 field theories in 2+1 dimensions.Comment: 32 pages, LateX, v2: minor changes, reference added, v3: section
3.5.2 improve
Chern-Simons Vortices in Supergravity
We study supersymmetric vortex solutions in three-dimensional abelian gauged
supergravity. First, we construct the general U(1)-gauged D=3, N=2 supergravity
whose scalar sector is an arbitrary Kahler manifold with U(1) isometry. This
construction clarifies the connection between local supersymmetry and the
specific forms of some scalar potentials previously found in the literature --
in particular, it provides the locally supersymmetric embedding of the abelian
Chern-Simons Higgs model. We show that the Killing spinor equations admit
rotationally symmetric vortex solutions with asymptotically conical geometry
which preserve half of the supersymmetry.Comment: 26 pages, LaTeX2
Multi-Instanton Calculus and Equivariant Cohomology
We present a systematic derivation of multi-instanton amplitudes in terms of
ADHM equivariant cohomology. The results rely on a supersymmetric formulation
of the localization formula for equivariant forms. We examine the cases of N=4
and N=2 gauge theories with adjoint and fundamental matter.Comment: 29 pages, one more reference adde
Mirror Symmetry and a Flop
By applying mirror symmetry to D-branes in a Calabi-Yau geometry we shed
light on a flop in M-theory relevant for large dualities in supersymmetric gauge theories. Furthermore, we derive superpotential for
M-theory on corresponding manifolds for all A-D-E cases. This provides an
effective method for geometric engineering of gauge theories for
which mirror symmetry gives exact information about vacuum geometry. We also
find a number of interesting dual descriptions.Comment: Identification of parameters as well as the computation of the
superpotential is extended to all A-D-E cases. Additional references are also
include
Branes with fluxes wrapped on spheres
Following an eight-dimensional gauged supergravity approach we construct the
most general solution describing D6-branes wrapped on a Kahler four-cycle taken
to be the product of two spheres of different radii. Our solution interpolates
between a Calabi-Yau four-fold and the spaces S^2xS^2xS^2xR^2 or S^2xS^2xR^4,
depending on generic choices for the parameters. Then we turn on a background
four-form field strength, corresponding to D2-branes, and show explicitly how
our solution is deformed. For a particular choice of parameters it represents a
flow from a Calabi-Yau four-fold times the three-dimensional Minkowski
space-time in the ultraviolet, to the space-time AdS_4xQ^{1,1,1} in the
infrared. In general, the solution in the infrared has a singularity which
within type-IIA supergravity corresponds to the near horizon geometry of the
solution for the D2-D6 system. Finally, we uncover the relation with work done
in the eighties on Freund-Rubin type compactifications.Comment: 15 pages, Late
Hydrodynamics from the Dp-brane
We complete the computation of viscous transport coefficients in the near
horizon geometries that arise from a stack of black Dp-branes for p=2,...,6 in
the decoupling limit. The main new result is the obtention of the bulk
viscosity which, for all p, is found to be related to the speed of sound by the
simple relation \zeta/\eta = -2(v_s^2-1/p). For completeness the shear
viscosity is rederived from gravitational perturbations in the shear and scalar
channels. We comment on technical issues like the counterterms needed, or the
possible dependence on the conformal frame.Comment: 15 page
BPS String Solutions in Non-Abelian Yang-Mills Theories and Confinement
Starting from the bosonic part of N=2 Super QCD with a 'Seiberg-Witten' N=2
breaking mass term, we obtain string BPS conditions for arbitrary semi-simple
gauge groups. We show that the vacuum structure is compatible with a symmetry
breaking scheme which allows the existence of Z_k-strings and which has
Spin(10) -> SU(5) x Z_2 as a particular case. We obtain BPS Z_k-string
solutions and show that they satisfy the same first order differential
equations as the BPS string for the U(1) case. We also show that the string
tension is constant, which may cause a confining potential between monopoles
increasing linearly with their distance.Comment: 11 pages, Latex. Minor changes to the text. Final version to appear
in Phys. Rev.
- âŠ