18,747 research outputs found
Wilson Loops and Chiral Correlators on Squashed Sphere
We study chiral deformations of and supersymmetric
gauge theories obtained by turning on
interactions with the superfield. Using localization, we
compute the deformed gauge theory partition function and the
expectation value of circular Wilson loops on a squashed four-sphere. In
the case of the deformed theory, exact formulas for and
are derived in terms of an underlying interacting matrix model replacing
the free Gaussian model describing the theory. Using the AGT
correspondence, the -deformations are related to the insertions of
commuting integrals of motion in the four-point CFT correlator and chiral
correlators are expressed as -derivatives of the gauge theory partition
function on a finite -background. In the so called Nekrasov-Shatashvili
limit, the entire ring of chiral relations is extracted from the
-deformed Seiberg-Witten curve. As a byproduct of our analysis we
show that gauge theories on rational -backgrounds are dual to
CFT minimal models.Comment: 33 pages, 2 figure, in this version we have added two new references
and a detailed comparison with the results obtained in one of these tw
Probing Fuzzballs with Particles, Waves and Strings
We probe D1D5 micro-state geometries with massless particles, waves and
strings. To this end, we study geodetic motion, Klein-Gordon equation and
string scattering in the resulting gravitational background. Due to the reduced
rotational symmetry, even in the simple case of a circular fuzzball, the system
cannot be integrated elementarily. Yet, for motion in the plane of the string
profile or in the orthogonal plane to it, one can compute the deflection angle
or the phase shift and identify the critical impact parameter, at which even a
massless probe is captured by the fuzzball if its internal momentum is properly
tuned. We find agreement among the three approaches, thus giving further
support to the fuzzball proposal at the dynamical level.Comment: 35 pages. Extended and improved discussions on the integrability of
the geodetic equations and on the critical impact parameter
Dynamical Supersymmetry Breaking in Intersecting Brane Models
In this paper we study dynamical supersymmetry breaking in absence of gravity
with the matter content of the minimal supersymmetric standard model. The
hidden sector of the theory is a strongly coupled gauge theory, realized in
terms of microscopic variables which condensate to form mesons. The
supersymmetry breaking scalar potential combines F, D terms with instanton
generated interactions in the Higgs-mesons sector. We show that for a large
region in parameter space the vacuum breaks in addition to supersymmetry also
electroweak gauge symmetry. We furthermore present local D-brane configurations
that realize these supersymmetry breaking patterns.Comment: 30 pages, 4 figures, pdflate
Partition Functions of Pure Spinors
We compute partition functions describing multiplicities and charges of
massless and first massive string states of pure-spinor superstrings in
3,4,6,10 dimensions. At the massless level we find a spin-one gauge multiplet
of minimal supersymmetry in d dimensions. At the first massive string level we
find a massive spin-two multiplet. The result is confirmed by a direct analysis
of the BRST cohomology at ghost number one. The central charges of the pure
spinor systems are derived in a manifestly SO(d) covariant way confirming that
the resulting string theories are critical. A critical string model with
N=(2,0) supersymmetry in d=2 is also described.Comment: LaTex, 30 p
A note on supersymmetric D-brane dynamics
We study the spin dependence of D-brane dynamics in the Green-Schwarz
formalism of boundary states. In particular we show how to interpret insertion
of supercharges on the boundary state as sources of non-universal spin effects
in D-brane potentials. In this way we find for a generic (D)p-brane, potentials
going like corresponding to interactions between the
different components of the D-brane supermultiplet. From the eleven dimensional
point of view, these potentials arise from the exchange of field strengths
corresponding to the graviton and the three form, coupled non-minimally to the
branes. We show how an annulus computation truncated to its massless
contribution is enough to reproduce these next-to-leading effects, meaning in
particular that the one-loop (M)atrix theory effective action should encode all
the spin dependence of low-energy supergravity interactions.Comment: LaTex file, 12 pages, no figures, some corrections in last section
and references added; version to appear in Physics Letters
S-duality and the prepotential in N=2* theories (I): the ADE algebras
The prepotential of N=2* supersymmetric theories with unitary gauge groups in
an Omega-background satisfies a modular anomaly equation that can be
recursively solved order by order in an expansion for small mass. By requiring
that S-duality acts on the prepotential as a Fourier transform we generalise
this result to N=2* theories with gauge algebras of the D and E type and show
that their prepotentials can be written in terms of quasi-modular forms of
SL(2,Z). The results are checked against microscopic multi-instanton calculus
based on localization for the A and D series and reproduce the known
1-instanton prepotential of the pure N=2 theories for any gauge group of ADE
type. Our results can also be used to obtain the multi-instanton terms in the
exceptional theories for which the microscopic instanton calculus and the ADHM
construction are not available.Comment: 33 pages, LaTeX2e, added references, version to be published in JHE
On the perturbative corrections around D-string instantons
We study -threshold corrections in an eight dimensional S-dual
pair of string theories, as a prototype of dual string vacua with sixteen
supercharges. We show that the orbifold CFT description of D-string instantons
gives rise to a perturbative expansion similar to the one appearing on the
fundamental string side. By an explicit calculation, using the Nambu-Goto
action in the static gauge, we show that the first subleading term agrees
precisely on the two sides. We then give a general argument to show that the
agreement extends to all orders.Comment: 12 page
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