1,018 research outputs found
A Field-Theoretic Approach to Connes' Gauge Theory on
Connes' gauge theory on is reformulated in the Lagrangian
level. It is pointed out that the field strength in Connes' gauge theory is not
unique. We explicitly construct a field strength different from Connes' one and
prove that our definition leads to the generation-number independent Higgs
potential. It is also shown that the nonuniqueness is related to the assumption
that two different extensions of the differential geometry are possible when
the extra one-form basis is introduced to define the differential
geometry on . Our reformulation is applied to the standard model
based on Connes' color-flavor algebra. A connection between the unimodularity
condition and the electric charge quantization is then discussed in the
presence or absence of .Comment: LaTeX file, 16 page
Impulsive noise removal from color images with morphological filtering
This paper deals with impulse noise removal from color images. The proposed
noise removal algorithm employs a novel approach with morphological filtering
for color image denoising; that is, detection of corrupted pixels and removal
of the detected noise by means of morphological filtering. With the help of
computer simulation we show that the proposed algorithm can effectively remove
impulse noise. The performance of the proposed algorithm is compared in terms
of image restoration metrics and processing speed with that of common
successful algorithms.Comment: The 6th international conference on analysis of images, social
networks, and texts (AIST 2017), 27-29 July, 2017, Moscow, Russi
BRST invariant formulation of spontaneously broken gauge theory in generalized differential geometry
Noncommutative geometry(NCG) on the discrete space successfully reproduces
the Higgs mechanism of the spontaneously broken gauge theory, in which the
Higgs boson field is regarded as a kind of gauge field on the discrete space.
We could construct the generalized differential geometry(GDG) on the discrete
space which is very close to NCG in case of .
GDG is a direct generalization of the differential geometry on the ordinary
manifold into the discrete one. In this paper, we attempt to construct the BRST
invariant formulation of spontaneously broken gauge theory based on GDG and
obtain the BRST invariant Lagrangian with the t'Hooft-Feynman gauge fixing
term.Comment: 15 page
Exact Analysis of ESR Shift in the Spin-1/2 Heisenberg Antiferromagnetic Chain
A systematic perturbation theory is developed for the ESR shift and is
applied to the spin-1/2 Heisenberg chain. Using the Bethe ansatz technique, we
exactly analyze the resonance shift in the first order of perturbative
expansion with respect to an anisotropic exchange interaction. Exact result for
the whole range of temperature and magnetic field, as well as asymptotic
behavior in the low-temperature limit are presented. The obtained g-shift
strongly depends on magnetic fields at low temperature, showing a significant
deviation from the previous classical result.Comment: 4 pages, 3 figures,to be published in Phys. Rev. Let
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Enantioselective Synthesis of Dialkylated N-Heterocycles by Palladium-Catalyzed Allylic Alkylation
The enantioselective synthesis of α-disubstituted N-heterocyclic carbonyl compounds has been accomplished using palladium-catalyzed allylic alkylation. These catalytic conditions enable access to various heterocycles, such as morpholinone, thiomorpholinone, oxazolidin-4-one, 1,2-oxazepan-3-one, 1,3-oxazinan-4-one, and structurally related lactams, all bearing fully substituted α-positions. Broad functional group tolerance was explored at the α-position in the morpholinone series. We demonstrate the utility of this method by performing various transformations on our useful products to readily access a number of enantioenriched compounds
Detection of a Fully-resolved Compton Shoulder of the Iron K-alpha Line in the Chandra X-ray Spectrum of GX 301-2
We report the detection of a fully-resolved, Compton-scattered emission line
in the X-ray spectrum of the massive binary GX 301-2 obtained with the High
Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory.
The iron K-alpha fluorescence line complex observed in this system consists of
an intense narrow component centered at an energy of E = 6.40 keV and a redward
shoulder that extends down to ~6.24 keV, which corresponds to an energy shift
of a Compton back-scattered iron K-alpha photon. From detailed Monte Carlo
simulations and comparisons with the observed spectra, we are able to directly
constrain the physical properties of the scattering medium, including the
electron temperature and column density, as well as an estimate for the metal
abundance.Comment: 13 pages, 4 figures, 1 table, accepted for publication in ApJ Lette
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