3,847 research outputs found
Nuclear phenomena derived from quark-gluon strings
We propose a QCD based many-body model for the nucleus where the strong
coupling regime is controlled by a three body string force and the weak
coupling regime is dominated by a pairing force. This model operates
effectively with a quark-gluon Lagrangian containing a pairing force from
instantons and a baryonic string term which contains a confining potential. The
unified model for weak and strong coupling regimes, is, however, only
consistent at the border of perturbative QCD. The baryonic string force is
necessary, as a {stability and} compressibility analysis shows, for the
occurrence of the phases of nuclear matter. The model exhibits a quark
deconfinement transition and chiral restoration which are suggested by QCD and
give qualitatively correct numerics. The effective model is shown to be
isomorphic to the Nambu-Jona-Lasinio model and exhibits the correct chirality
provided that the chiral fields are identified with the 2-particle strings,
which are natural in a QCD frameworkComment: 17 pages, 4 figures, 2 table
Representation of SU(infinity) Algebra for Matrix Models
We investigate how the matrix representation of SU(N) algebra approaches that
of the Poisson algebra in the large N limit. In the adjoint representation, the
(N^2-1) times (N^2-1) matrices of the SU(N) generators go to those of the
Poisson algebra in the large N limit. However, it is not the case for the N
times N matrices in the fundamental representation.Comment: 8 page
Import/Export in Digital Rights Management
The inherently controlled nature of digital rights management systems does little to promote inter-operability of systems provided by different vendors. In this paper, we consider import and export functionality by which multimedia protected by one digital rights management regime can be made available to a multimedia device that supports a different digital rights management regime, without compromising the protection afforded to the content under the original regime. We first identify specific issues to be addressed by developers of digital rights management import/export regimes and outline a variety of methods by which these regimes may be implemented. We then apply our observations to the specific example of import and export of content between the digital rights management regimes defined by the Motion Picture Exports Group and the Open Mobile Alliance
Spatial and temporal filtering of a 10-W Nd:YAG laser with a Fabry-Perot ring-cavity premode cleaner
We report on the use of a fixed-spacer Fabry–Perot ring cavity to filter spatially and temporally a 10-W laser-diode-pumped Nd:YAG master-oscillator power amplifier. The spatial filtering leads to a 7.6-W TEMinfinity beam with 0.1% higher-order transverse mode content. The temporal filtering reduces the relative power fluctuations at 10 MHz to 2.8 x 10^-/sqrtHz, which is 1 dB above the shot-noise limit for 50 mA of detected photocurrent
Perturbation Theory for a Repulsive Hubbard Model in Quasi-One-Dimensional Superconductors
We investigate pairing symmetry and a transition temperature in a
quasi-one-dimensional repulsive Hubbard model. We solve the Eliashberg equation
using the third-order perturbation expansion with respect to the on-site
repulsion . We find that when the electron number density is shifted from
the half-filled, a transition into unconventional superconductivity is
expected. When one dimensionality is weak, a spin-singlet state is favorable.
By contrast, when one dimensionality is strong and electron number density is
far from the half-filled, a spin-triplet state is stabilized. Finally, we
discuss the possibility of unconventional superconductivity caused by the
on-site Coulomb repulsion in -NaVO.Comment: 4 pages, 7 figure
Sublinear Estimation of Weighted Matchings in Dynamic Data Streams
This paper presents an algorithm for estimating the weight of a maximum
weighted matching by augmenting any estimation routine for the size of an
unweighted matching. The algorithm is implementable in any streaming model
including dynamic graph streams. We also give the first constant estimation for
the maximum matching size in a dynamic graph stream for planar graphs (or any
graph with bounded arboricity) using space which also
extends to weighted matching. Using previous results by Kapralov, Khanna, and
Sudan (2014) we obtain a approximation for general graphs
using space in random order streams, respectively. In
addition, we give a space lower bound of for any
randomized algorithm estimating the size of a maximum matching up to a
factor for adversarial streams
Scaling Properties of Antiferromagnetic Transition in Coupled Spin Ladder Systems Doped with Nonmagnetic Impurities
We study effects of interladder coupling on critical magnetic properties of
spin ladder systems doped with small concentrations of nonmagnetic impurities,
using the scaling theory together with quantum Monte Carlo (QMC) calculations.
Scaling properties in a wide region in the parameter space of the impurity
concentration x and the interladder coupling are governed by the quantum
critical point (QCP) of the undoped system for the transition between
antiferromagnetically ordered and spin-gapped phases. This multi-dimensional
and strong-coupling region has characteristic power-law dependences on x for
magnetic properties such as the N\'eel temperature. The relevance of this
criticality for understanding experimental results of ladder compounds is
stressed.Comment: 4 pages LaTeX including 3 PS figure
A critical-density closed Universe in Brans-Dicke theory
In a Brans-Dicke (BD) cosmological model, the energy density associated with
some scalar field decreases as \displaystyle a^{{-2}(\frac{\omega_{o}+
{\frac12}%}{\omega_{o}+1})} with the scale factor of the Universe,
giving a matter with an Equation of state . In this model, the Universe
could be closed but still have a nonrelativistic-matter density corresponding
to its critical value, . Different cosmological expressions, such
as, luminosity distance, angular diameter, number count and ratio of the
redshift tickness-angular size, are determined in terms of the redshift for
this model.Comment: To appear in MNRAS, 7 pages, 5 eps figure
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