69 research outputs found
N=1 gauge superpotentials from supergravity
We review the supergravity derivation of some non-perturbatively generated
effective superpotentials for N=1 gauge theories. Specifically, we derive the
Veneziano-Yankielowicz superpotential for pure N=1 Super Yang-Mills theory from
the warped deformed conifold solution, and the Affleck-Dine-Seiberg
superpotential for N=1 SQCD from a solution describing fractional D3-branes on
a C^3 / Z_2 x Z_2 orbifold.Comment: LaTeX, iopart class, 8 pages, 3 figures. Contribution to the
proceedings of the workshop of the RTN Network "The quantum structure of
space-time and the geometric nature of fundamental interactions", Copenhagen,
September 2003; v2: published version with minor clarification
Aspects of ALE Matrix Models and Twisted Matrix Strings
We examine several aspects of the formulation of M(atrix)-Theory on ALE
spaces. We argue for the existence of massless vector multiplets in the
resolved spaces, as required by enhanced gauge symmetry in M-Theory,
and that these states might have the correct gravitational interactions. We
propose a matrix model which describes M-Theory on an ALE space in the presence
of wrapped membranes. We also consider orbifold descriptions of matrix string
theories, as well as more exotic orbifolds of these models, and present a
classification of twisted matrix string theories according to Reid's exact
sequences of surface quotient singularities.Comment: 27 pages LaTeX2e, 7 figures, using utarticle.cls (included),
array.sty, amsmath.sty, amsfonts.sty, cite.sty, epsf.sty. Bibtex style:
utphys.bst (.bbl file included). Section on wrapped membrane states revised
and expanded. We now argue for the existence of wrapped membranes and propose
a matrix model which describes M-Theory on an ALE space in the presence of
wrapped membrane
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
PP Wave Limit and Enhanced Supersymmetry in Gauge Theories
We observe that the pp wave limit of compactifications of
type IIB string theory is universal, and maximally supersymmetric, as long as
is smooth and preserves some supersymmetry. We investigate a specific
case, . The dual SCFT, describing D3-branes at a
conifold singularity, has operators that we identify with the oscillators of
the light-cone string in the universal pp-wave background. The correspondence
is remarkable in that it relies on the exact spectrum of anomalous dimensions
in this CFT, along with the existence of certain exceptional series of
operators whose dimensions are protected only in the limit of large `t Hooft
coupling. We also briefly examine the singular case , for which
the pp wave background becomes a orbifold of the maximally supersymmetric
background by reflection of 4 transverse coordinates. We find operators in the
corresponding SCFT with the right properties to describe both the
untwisted and the twisted sectors of the closed string.Comment: 15 pages, LaTeX; v2: added more detail to a derivation, and a
preprint number; v3: minor corrections, some remarks and references adde
Non-perturbative gauge superpotentials from supergravity
We study U(N) SQCD with N_f <= N flavors of quarks and antiquarks by
engineering it with a configuration of fractional D3-branes on a C^3 / Z_2 x
Z_2 orbifold. In particular we show how the moduli space of the gauge theory
naturally emerges from the classical geometry produced by the D3-branes, and
how the non-perturbatively generated superpotential is recovered from
geometrical data.Comment: LaTeX, 18 pages, 4 figures; v2: published version with minor changes
and an added referenc
An N=1 duality cascade from a deformation of N=4 SUSY Yang-Mills
We study relevant deformations of an N=1 superconformal theory which is an
exactly marginal deformation of U(N) N=4 SUSY Yang-Mills. The resulting theory
has a classical Higgs branch that is a complex deformation of the orbifold
C^3/Z_n x Z_n that is a non-compact Calabi-Yau space with isolated conifold
singularities. At these singular points in moduli space the theory exhibits a
duality cascade and flows to a confining theory with a mass gap. By exactly
solving the corresponding holomorphic matrix model we compute the exact quantum
superpotential generated at the end of the duality cascade and calculate
precisely how quantum effects deform the classical moduli space by replacing
the conifold singularities with three-cycles of finite size. Locally the
structure is that of the deformed conifold, but the global geometry is
different. This desingularized quantum deformed geometry is the moduli space of
probe D3-branes at the end of a duality cascade realized on the worldvolume of
(fractional) D3-branes placed at the isolated conifold singularities in the
deformation of the orbifold C^3/Z_n x Z_n with discrete torsion.Comment: Uses Latex, JHEP.cls, 43 pages, 3 figure
A Point's Point of View of Stringy Geometry
The notion of a "point" is essential to describe the topology of spacetime.
Despite this, a point probably does not play a particularly distinguished role
in any intrinsic formulation of string theory. We discuss one way to try to
determine the notion of a point from a worldsheet point of view. The derived
category description of D-branes is the key tool. The case of a flop is
analyzed and Pi-stability in this context is tied in to some ideas of
Bridgeland. Monodromy associated to the flop is also computed via Pi-stability
and shown to be consistent with previous conjectures.Comment: 15 pages, 3 figures, ref adde
On Penrose limit of elliptic branes
We discuss a Penrose limit of an elliptic brane configuration with NS5
and D4 branes. This background is T-dual to D3 branes at a fixed
point of a singularity and the T-duality
survives the Penrose limit. The triple scaling limit of and gives
rise to IIA pp-wave solution with a space-like compact direction. We identify
the quiver gauge theory operators and argue that upon exchange of the momentum
along the compact direction and the winding number these operators coincide
with the operators derived in the dual type IIB description. We also find a new
Penrose limit of the type IIB background and the corresponding limit in the
type IIA picture. In the coordinate system we use there are two manifest
space-like isometries. The quiver gauge theory operator duals of the string
states are built of three bosonic fields.Comment: 25 pages with 1 figur
A toy model for the AdS/CFT correspondence
We study the large N gauged quantum mechanics for a single Hermitian matrix
in the Harmonic oscillator potential well as a toy model for the AdS/CFT
correspondence. We argue that the dual geometry should be a string in two
dimensions with a curvature of stringy size. Even though the dual geometry is
not weakly curved, one can still gain knowledge of the system from a detailed
study of the open-closed string duality. We give a mapping between the basis of
states made of traces (closed strings) and the eigenvalues of the matrix
(D-brane picture) in terms of Schur polynomials. We connect this model with the
study of giant gravitons in AdS_5 x S^5. We show that the two giant gravitons
that expand along AdS_5 and S^5 can be interpreted in the matrix model as
taking an eigenvalue from the Fermi sea and exciting it very much, or as making
a hole in the Fermi sea respectively. This is similar to recent studies of the
c=1 string. This connection gives new insight on how to perform calculations
for giant gravitons.Comment: 19 pages JHEP, 4 figures. v2: comments added, typos fixed, additional
refs. v3: The paper has been largely revised, to make the relation as a limit
of N=4 SYM clear, also some proofs have been written in full rather than
sketched. This updated version reflects the changes that were made in the
published versio
Stringy Instantons and Quiver Gauge Theories
We explore contributions to the 4D effective superpotential which arise from
Euclidean D3 branes (``instantons'') that intersect space-filling D-branes.
These effects can perturb the effective field theory on the space-filling
branes by nontrivial operators composed of charged matter fields, changing the
vacuum structure in a qualitative way in some examples. Our considerations are
exemplified throughout by a careful study of a fractional brane configuration
on a del Pezzo surface.Comment: 30 pages, 4 figures; v2: reference added; v3: confusing minor error
in axion charges fixed (thanks to D. Green for pointing it out
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