15,140 research outputs found
Regularizing Cubic Open Neveu-Schwarz String Field Theory
After introducing non-minimal variables, the midpoint insertion of Y\bar Y in
cubic open Neveu-Schwarz string field theory can be replaced with an operator
N_\rho depending on a constant parameter \rho. As in cubic open superstring
field theory using the pure spinor formalism, the operator N_\rho is invertible
and is equal to 1 up to a BRST-trivial quantity. So unlike the linearized
equation of motion Y\bar Y QV=0 which requires truncation of the Hilbert space
in order to imply QV=0, the linearized equation N_\rho QV=0 directly implies
QV=0.Comment: 6 pages harvmac, added footnote and referenc
Green-Schwarz Formulation of Self-Dual Superstring
The self-dual superstring has been described previously in a
Neveu-Schwarz-Ramond formulation with local N=2 or 4 world-sheet supersymmetry.
We present a Green-Schwarz-type formulation, with manifest spacetime
supersymmetry.Comment: 11 pg., (uuencoded dvi file) ITP-SB-92-5
Non-ideal artificial phase discontinuity in long Josephson 0-kappa-junctions
We investigate the creation of an arbitrary -discontinuity of the
Josephson phase in a long Nb-AlO_x-Nb Josephson junction (LJJ) using a pair of
tiny current injectors, and study the formation of fractional vortices formed
at this discontinuity. The current I_inj, flowing from one injector to the
other, creates a phase discontinuity kappa ~ I_inj. The calibration of
injectors is discussed in detail. The small but finite size of injectors leads
to some deviations of the properties of such a 0-kappa-LJJ from the properties
of a LJJ with an ideal kappa-discontinuity. These experimentally observed
deviations in the dependence of the critical current on I_inj$ and magnetic
field can be well reproduced by numerical simulation assuming a finite injector
size. The physical origin of these deviations is discussed.Comment: Submitted to Phys. Rev. B (12 figures). v 2: refs updated, long eqs
fixed v 3: major changes, fractional vortex dynamics exclude
The N=2(4) string is self-dual N=4 Yang-Mills
N=2 string amplitudes, when required to have the Lorentz covariance of the
equivalent N=4 string, describe a self-dual form of N=4 super Yang-Mills in 2+2
dimensions. Spin-independent couplings and the ghost nature of SO(2,2)
spacetime make it a topological-like theory with vanishing loop corrections.Comment: 7 pg., ITP-SB-92-24 (uuencoded dvi file; otherwise same as original
Snyder noncommutative space-time from two-time physics
We show that the two-time physics model leads to a mechanical system with
Dirac brackets consistent with the Snyder noncommutative space. An Euclidean
version of this space is also obtained and it is shown that both spaces have a
dual system describing a particle in a curved space-time.Comment: 5 pages, RevTeX4. References adde
Two-Stage Convolutional Neural Network for Breast Cancer Histology Image Classification
This paper explores the problem of breast tissue classification of microscopy
images. Based on the predominant cancer type the goal is to classify images
into four categories of normal, benign, in situ carcinoma, and invasive
carcinoma. Given a suitable training dataset, we utilize deep learning
techniques to address the classification problem. Due to the large size of each
image in the training dataset, we propose a patch-based technique which
consists of two consecutive convolutional neural networks. The first
"patch-wise" network acts as an auto-encoder that extracts the most salient
features of image patches while the second "image-wise" network performs
classification of the whole image. The first network is pre-trained and aimed
at extracting local information while the second network obtains global
information of an input image. We trained the networks using the ICIAR 2018
grand challenge on BreAst Cancer Histology (BACH) dataset. The proposed method
yields 95 % accuracy on the validation set compared to previously reported 77 %
accuracy rates in the literature. Our code is publicly available at
https://github.com/ImagingLab/ICIAR2018Comment: 10 pages, 5 figures, ICIAR 2018 conferenc
Homotopy Lie Superalgebra in Yang-Mills Theory
The Yang-Mills equations are formulated in the form of generalized
Maurer-Cartan equations, such that the corresponding algebraic operations are
shown to satisfy the defining relations of homotopy Lie superalgebra.Comment: LaTeX2e, 10 page
Self-Dual N=8 Supergravity as Closed N=2(4) Strings
As open N=2 or 4 strings describe self-dual N=4 super Yang-Mills in 2+2
dimensions, the corresponding closed (heterotic) strings describe self-dual
ungauged (gauged) N=8 supergravity. These theories are conveniently formulated
in a chiral superspace with general supercoordinate and local OSp(8|2) gauge
invariances. The super-light-cone and covariant-component actions are analyzed.
Because only half the Lorentz group is gauged, the gravity field equation is
just the vanishing of the torsion.Comment: 17 pg., (uuencoded dvi file; revision: forgot 1 stupid term in the
last equation) ITP-SB-92-3
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