69,954 research outputs found
Quantum Higgs branches of isolated N=2 superconformal field theories
We study the Higgs branches of the superconformal points of four-dimensional
N=2 super Yang-Mills (SYM) which appear due to the occurrence of mutually local
monopoles having appropriate charges. We show, for example, that the maximal
superconformal point of SU(2n) SYM has a Higgs branch of the form C^2/Z_n.
These Higgs branches are intrinsic to the superconformal field theory (SCFT) at
the superconformal point, but do not appear in the SYM theory in which it is
embedded. This is because the embedding is a UV extension of the SCFT in which
some global symmetry acting on the Higgs branch is gauged irrelevantly. Higgs
branches deduced from earlier direct studies of these isolated SCFTs using BPS
wall-crossing or 3-d mirror symmetry agree with the ones we find here using
just the Seiberg-Witten data for the SYM theories.Comment: 18 page
Tinkertoys for Gaiotto Duality
We describe a procedure for classifying N=2 superconformal theories of the
type introduced by Davide Gaiotto. Any curve, C, on which the 6D A_{N-1} SCFT
is compactified, can be decomposed into 3-punctured spheres, connected by
cylinders. We classify the spheres, and the cylinders that connect them. The
classification is carried out explicitly, up through N=5, and for several
families of SCFTs for arbitrary N. These lead to a wealth of new S-dualities
between Lagrangian and non-Lagrangian N=2 SCFTs.Comment: 61 pages, 136 figures (a veritable comic book). V2: Grotty bitmapped
figures replaced with PDF versions; a couple of references fixe
Argyres-Douglas Loci, Singularity Structures and Wall-Crossings in Pure N=2 Gauge Theories with Classical Gauge Groups
N=2 Seiberg-Witten theories allow an interesting interplay between the
Argyres-Douglas loci, singularity structures and wall-crossing formulae. In
this paper we investigate this connection by first studying the singularity
structures of hyper-elliptic Seiberg-Witten curves for pure N=2 gauge theories
with SU(r+1) and Sp(2r) gauge groups, and propose new methods to locate the
Argyres-Douglas loci in the moduli space, where multiple mutually non-local BPS
states become massless. In a region of the moduli space, we compute dyon
charges for all 2r+2 and 2r+1 massless dyons for SU(r+1) and Sp(2r) gauge
groups respectively for rank r>1. From here we elucidate the connection to the
wall-crossing phenomena for pure Sp(4) Seiberg-Witten theory near the
Argyres-Douglas loci, despite our emphasis being only at the massless sector of
the BPS spectra. We also present 2r-1 candidates for the maximal
Argyres-Douglas points for pure SO(2r+1) Seiberg-Witten theory.Comment: 81 pages, 41 figures, LaTeX; v2: Minor cosmetic changes and
correction of a typographical error in acknowledgement. Final version to
appear in JHE
Comments on scaling limits of 4d N=2 theories
We revisit the study of the maximally singular point in the Coulomb branch of
4d N=2 SU(N) gauge theory with N_f=2n flavors for N_f= 2, we find
that the low-energy physics is described by two non-trivial superconformal
field theories coupled to a magnetic SU(2) gauge group which is infrared free.
(In the special case n=2, one of these theories is a theory of free
hypermultiplets.) This observation removes a possible counter example to a
conjectured a-theorem.Comment: 13 page
More Three Dimensional Mirror Pairs
We found a lot of new three dimensional N = 4 mirror pairs generalizing
previous considerations on three dimensional generalized quiver gauge theories.
We recovered almost all previous discovered mirror pairs with these
constructions. One side of these mirror pairs are always the conventional
quiver gauge theories. One of our result can also be used to determine the
matter content and weakly coupled gauge groups of four dimensional N = 2
generalized quiver gauge theories derived from six dimensional A_N and D_N
theory, therefore we explicitly constructed four dimensional S-duality pairs.Comment: 33 pages, 18 figures version2 minor correction
Optical binding of magnetodielectric Rayleigh particles
We present a theoretical and numerical study of the optical binding and optical torque between two Rayleigh particles with arbitrary, complex, scalar dielectric permittivity and magnetic permeability. We use a computational approach based on the discrete dipole approximation to derive the optical force and torque experienced by the particles when illuminated by a linearly or circularly polarized plane wave. We show that optical binding between magnetodielectic particles is qualitatively different from the traditional case involving dielectric particles only. In particular, we show that for certain configurations, the system of two magnetodielectric particles will experience a long-range optical torque whose amplitude envelope does not decay with the separation between the particles. © 2013 American Physical Society
Dietary aflatoxin exposure and impaired growth in young children from Benin and Togo: cross sectional study
Fetal and early childhood environment, including the
nutritional status of the pregnant mother and the
infant, are considered critical for growth and risk of
disease in later life. Many people in developing coun
tries are not only malnourished but also chronically
exposed to high levels of toxic fungal metabolites
(mycotoxins). One family of mycotoxins, the aflatoxins,
are carcinogenic and immunotoxic and cause growth
retardation in animals. Aflatoxins contaminate staple
foods in West Africa, particularly maize and ground
nuts, as a result of hot, humid storage conditions that
promote fungal growth. High exposure to aflatoxins
occurs throughout childhood in the region, suggest
ing that growth and development could be critically
affected.We assessed exposure to aflatoxins in relation
to anthropometric measures in children in Benin and
Togo
Prevalence of Gastroesophageal Reflux in Cats During Anesthesia and Effect of Omeprazole on Gastric pH.
BackgroundGastroesophageal reflux (GER) is poorly characterized in anesthetized cats, but can cause aspiration pneumonia, esophagitis, and esophageal stricture formation.ObjectiveTo determine whether pre-anesthetic orally administered omeprazole increases gastric and esophageal pH and increases serum gastrin concentrations in anesthetized cats, and to determine the prevalence of GER using combined multichannel impedance and pH monitoring.AnimalsTwenty-seven healthy cats undergoing elective dental procedures.MethodsProspective, double-masked, placebo-controlled, randomized clinical trial. Cats were randomized to receive 2 PO doses of omeprazole (1.45-2.20 mg/kg) or an empty gelatin capsule placebo 18-24 hours and 4 hours before anesthetic induction. Blood for measurement of serum gastrin concentration was collected during anesthetic induction. An esophageal pH/impedance catheter was utilized to continuously measure esophageal pH and detect GER throughout anesthesia.ResultsMean gastric pH in the cats that received omeprazole was 7.2 ± 0.4 (range, 6.6-7.8) and was significantly higher than the pH in cats that received the placebo 2.8 ± 1.0 (range, 1.3-4.1; P < .001). Omeprazole administration was not associated with a significant increase in serum gastrin concentration (P = .616). Nine of 27 cats (33.3%) had ≥1 episode of GER during anesthesia.Conclusions and clinical relevancePre-anesthetic administration of 2 PO doses of omeprazole at a dosage of 1.45-2.20 mg/kg in cats was associated with a significant increase in gastric and esophageal pH within 24 hours, but was not associated with a significant increase in serum gastrin concentration. Prevalence of reflux events in cats during anesthesia was similar to that of dogs during anesthesia
Cervical Spondylotic Myelopathy Mimicking ALS
Cervical spondylotic myelopathy presenting with muscle wasting in upper extremities and insignificantsensory loss has been termed as cervical spondylotic amyotrophy. This condition has to be differentiatedfrom Amyotrophic lateral sclerosis which also has similar presentation. Here we present a case study ofcervical spondylotic myelopathy resembling Amyotrophic lateral sclerosis clinically
Argyres-Douglas theories and S-duality
This article is distributed under the terms of the Creative Commons
Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are creditedM.B. and T.N. are partly supported by the U.S. Department of Energy under grants DOE-SC0010008, DOE-ARRA-SC0003883, and DOE-DE-SC0007897.
This research was supported in part by the National Science Foundation under Grant No.
NSF PHY11-25915. S.G. is partially supported by the ERC Advanced Grant “SyDuGraM”,
by FNRS-Belgium (convention FRFC PDR T.1025.14 and convention IISN 4.4514.08) and by the “Communaut´e Francaise de Belgique” through the ARC progra
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