39,924 research outputs found
QCD color interactions between two quarks
We study the QCD color interactions between static two heavy quarks at zero
temperature in a quenched SU(3) lattice gauge simulation: in addition to the
standard singlet potentials, we calculate octet
potentials, symmetric and antisymmetric potentials. It is shown that the
antisymmetric channel behaves as a linearly rising potential at large
quark separations. We further find that the octet and symmetric
channels have the complex dependence on the distance; at short distances they
are repulsive forces, while at large distances, they show linearly rising
feature. Ratio of string tensions between singlet and
antisymmetric potentials is described in terms of the Casimir factor
Quark-Meson Coupling Model for a Nucleon
The quark-meson coupling model for a nucleon is considered. The model
describes a nucleon as an MIT bag, in which quarks are coupled to scalar and
vector mesons. A set of coupled equations for the quark and the meson fields
are obtained and are solved in a self-consistent way. It is shown that the mass
of a nucleon as a dressed MIT bag interacting with sigma- and omega-meson
fields significantly differs from the mass of a free MIT bag. A few sets of
model parameters are obtained so that the mass of a dressed MIT bag becomes the
nucleon mass. The results of our calculations imply that the self-energy of the
bag in the quark-meson coupling model is significant and needs to be considered
in doing the nuclear matter calculations.Comment: 3 figure
Charge Symmetry Violation in Nuclear Physics
The study of charge symmetry violation in nuclear physics is a potentially
enormous subject. Through a few topical examples we aim to show that it is not
a subject of peripheral interest but rather goes to the heart of our
understanding of hadronic systems.Comment: Invited talk at the Int. Conference on Weak and Electromagnetic
Interactions in Nuclei, Osaka, June 12-16 199
A canonical Frobenius structure
We show that it makes sense to speak of THE Frobenius manifold attached to a
convenient and nondegenerate Laurent polynomialComment: 24 page
Analytical Study of the Julia Set of a Coupled Generalized Logistic Map
A coupled system of two generalized logistic maps is studied. In particular
influence of the coupling to the behaviour of the Julia set in two dimensional
complex space is analyzed both analytically and numerically. It is proved
analytically that the Julia set disappears from the complex plane uniformly as
a parameter interpolates from the chaotic phase to the integrable phase, if the
coupling strength satisfies a certain condition.Comment: 30pages, 22figure
Ceramic powder for sintering materials
Surface activity of ceramic powders such as MgO and Al2O3, for use in sintering with sp. emphasis on their particle size, shape, particle size distribution, packing, and coexisting additives and impurities are reviewed
Chirality Selection in Open Flow Systems and in Polymerization
As an attempt to understand the homochirality of organic molecules in life, a
chemical reaction model is proposed where the production of chiral monomers
from achiral substrate is catalyzed by the polymers of the same enatiomeric
type. This system has to be open because in a closed system the enhanced
production of chiral monomers by enzymes is compensated by the associated
enhancement in back reaction, and the chiral symmetry is conserved. Open flow
without cross inhibition is shown to lead to the chirality selection in a
general model. In polymerization, the influx of substrate from the ambience and
the efflux of chiral products for purposes other than the catalyst production
make the system necessarily open. The chiral symmetry is found to be broken if
the influx of substrate lies within a finite interval. As the efficiency of the
enzyme increases, the maximum value of the enantiomeric excess approaches unity
so that the chirality selection becomes complete.Comment: 8 pages, 4 figure
Unusual field and temperature dependence of Hall effect in graphene
We calculate the classic Hall conductivity and mobility of the undoped and
doped (or in the gate voltage) graphene as a function of temperature, magnetic
field, and carrier concentration. Carrier collisions with defects and acoustic
phonons are taken into account. The Hall resistivity varies almost linearly
with temperature. The magnetic field dependence of resistivity and mobility is
anomalous in weak magnetic fields. There is the square root contribution from
the field in the resistivity. The Hall mobility diverges logarithmically with
the field for low doping.Comment: 4 pages, 5 figures, typos correcte
Properties of Color-Coulomb String Tension
We study the properties of the color-Coulomb string tension obtained from the
instantaneous part of gluon propagators in Coulomb gauge using quenched SU(3)
lattice simulation.
In the confinement phase, the dependence of the color-Coulomb string tension
on the QCD coupling constant is smaller than that of the Wilson loop string
tension. On the other hand, in the deconfinement phase, the color-Coulomb
string tension does not vanish even for , the temperature
dependence of which is comparable with the magnetic scaling, dominating the
high temperature QCD. Thus, the color-Coulomb string tension is not an order
parameter of QGP phase transition.Comment: 17 pages, 5 figures; one new figure added, typos corrected, version
to appear in PR
Dirac-Sobolev inequalities and estimates for the zero modes of massless Dirac operators
The paper analyses the decay of any zero modes that might exist for a
massless Dirac operator H:= \ba \cdot (1/i) \bgrad + Q, where is -matrix-valued and of order O(|\x|^{-1}) at infinity. The approach
is based on inversion with respect to the unit sphere in and
establishing embedding theorems for Dirac-Sobolev spaces of spinors which
are such that and lie in Comment: 11 page
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