605 research outputs found
Gauge theory, topological strings, and S-duality
We offer a derivation of the duality between the topological U(1) gauge
theory on a Calabi-Yau 3-fold and the topological A-model on the same manifold.
This duality was conjectured recently by Iqbal, Nekrasov, Okounkov, and Vafa.
We deduce it from the S-duality of the IIB superstring. We also argue that the
mirror version of this duality relates the topological B-model on a Calabi-Yau
3-fold and a topological sector of the Type IIA Little String Theory on the
same manifold.Comment: 9 pages, latex. v2: a footnote has been added. The footnote corrects
an inaccuracy in the original argument; the results are unchanged. v3:
exposition improve
Black Hole Attractors and the Topological String
A simple relationship of the form Z_BH = |Z_top|^2 is conjectured, where Z_BH
is a supersymmetric partition function for a four-dimensional BPS black hole in
a Calabi-Yau compactification of Type II superstring theory and Z_top is a
second-quantized topological string partition function evaluated at the
attractor point in moduli space associated to the black hole charges. Evidence
for the conjecture in a perturbation expansion about large graviphoton charge
is given. The microcanonical ensemble of BPS black holes can be viewed as the
Wigner function associated to the wavefunction defined by the topological
string partition function.Comment: 32 pages, harvma
Calculation of Forces at Focal Adhesions from Elastic Substrate Data: The Effect of Localized Force and the Need for Regularization
AbstractForces exerted by stationary cells have been investigated on the level of single focal adhesions by combining elastic substrates, fluorescence labeling of focal adhesions, and the assumption of localized force when solving the inverse problem of linear elasticity theory. Data simulation confirms that the inverse problem is ill-posed in the presence of noise and shows that in general a regularization scheme is needed to arrive at a reliable force estimate. Spatial and force resolution are restricted by the smoothing action of the elastic kernel, depend on the details of the force and displacement patterns, and are estimated by data simulation. Corrections arising from the spatial distribution of force and from finite substrate size are treated in the framework of a force multipolar expansion. Our method is computationally cheap and could be used to study mechanical activity of cells in real time
Supergravity description of field theories on curved manifolds and a no go theorem
In the first part of this paper we find supergravity solutions corresponding
to branes on worldvolumes of the form where is a
Riemann surface. These theories arise when we wrap branes on holomorphic
Riemann surfaces inside or CY manifolds. In some cases the theory at low
energies is a conformal field theory with two less dimensions. We find some
non-singular supersymmetric compactifications of M-theory down to . We
also propose a criterion for permissible singularities in supergravity
solutions.
In the second part of this paper, which can be read independently of the
first, we show that there are no non-singular Randall-Sundrum or de-Sitter
compactifications for large class of gravity theories.Comment: latex, 37 pages. v2: References adde
Multivalued Fields on the Complex Plane and Conformal Field Theories
In this paper a class of conformal field theories with nonabelian and
discrete group of symmetry is investigated. These theories are realized in
terms of free scalar fields starting from the simple systems and scalar
fields on algebraic curves. The Knizhnik-Zamolodchikov equations for the
conformal blocks can be explicitly solved. Besides of the fact that one obtains
in this way an entire class of theories in which the operators obey a
nonstandard statistics, these systems are interesting in exploring the
connection between statistics and curved space-times, at least in the two
dimensional case.Comment: (revised version), 30 pages + one figure (not included), (requires
harvmac.tex), LMU-TPW 92-1
Generating new dualities through the orbifold equivalence: a demonstration in ABJM and four-dimensional quivers
We show that the recently proposed large equivalence between ABJM
theories with Chern-Simons terms of different rank and level,
U(N_1)_{k_1}\times U(N_1)_{-k_1} and U(N_2)_{k_2}\times U(N_2)_{-k_2}, but the
same value of N' =N_1 k_1=N_2 k_2, can be explained using planar equivalence in
the mirror duals. The combination of S-dualities and orbifold equivalence can
be applied to other cases as well, with very appealing results. As an example
we show that two different quiver theories with k nodes can be easily shown to
be Seiberg dual through the orbifold equivalence, but it requires order k^2
steps to give a proof when Seiberg duality is performed node by node.Comment: 18 pages, 7 figures, minor changes and references adde
Anti-de Sitter/CFT Correspondence in Three-Dimensional Supergravity
Anti-de Sitter supergravity models are considered in three dimensions.
Precise asymptotic conditions involving a chiral projection are given on the
Rarita-Schwinger fields. Together with the known boundary conditions on the
bosonic fields, these ensure that the asymptotic symmetry algebra is the
superconformal algebra. The classical central charge is computed and found to
be equal to the one of pure gravity. It is also indicated that the asymptotic
degrees of freedom are described by 2D "induced supergravity" and that the
boundary conditions "transmute" the non-vanishing components of the WZW
supercurrent into the supercharges.Comment: Additional remarks in the extended case, added references, and small
misprints corrected. To appear in Phys. Rev. D. Latex, 19 pages, no figure
Lectures on BCOV holomorphic anomaly equations
The present article surveys some mathematical aspects of the BCOV holomorphic
anomaly equations introduced by Bershadsky, Cecotti, Ooguri and Vafa. It grew
from a series of lectures the authors gave at the Fields Institute in the
Thematic Program of Calabi-Yau Varieties in the fall of 2013.Comment: reference added, typos correcte
ABCD of Beta Ensembles and Topological Strings
We study beta-ensembles with Bn, Cn, and Dn eigenvalue measure and their
relation with refined topological strings. Our results generalize the familiar
connections between local topological strings and matrix models leading to An
measure, and illustrate that all those classical eigenvalue ensembles, and
their topological string counterparts, are related one to another via various
deformations and specializations, quantum shifts and discrete quotients. We
review the solution of the Gaussian models via Macdonald identities, and
interpret them as conifold theories. The interpolation between the various
models is plainly apparent in this case. For general polynomial potential, we
calculate the partition function in the multi-cut phase in a perturbative
fashion, beyond tree-level in the large-N limit. The relation to refined
topological string orientifolds on the corresponding local geometry is
discussed along the way.Comment: 33 pages, 1 figur
Supersymmetric Extension of GCA in 2d
We derive the infinite dimensional Supersymmetric Galilean Conformal Algebra
(SGCA) in the case of two spacetime dimensions by performing group contraction
on 2d superconformal algebra. We also obtain the representations of the
generators in terms of superspace coordinates. Here we find realisations of the
SGCA by considering scaling limits of certain 2d SCFTs which are non-unitary
and have their left and right central charges become large in magnitude and
opposite in sign. We focus on the Neveu-Schwarz sector of the parent SCFTs and
develop, in parallel to the GCA studies recently in (arXiv:0912.1090), the
representation theory based on SGCA primaries, Ward identities for their
correlation functions and their descendants which are null states.Comment: La TeX file, 32 pages; v2: typos corrected, journal versio
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