126,926 research outputs found
Multiple Chirality in Nuclear Rotation: A Microscopic View
Covariant density functional theory and three-dimensional tilted axis
cranking are used to investigate multiple chirality in nuclear rotation for the
first time in a fully self-consistent and microscopic way. Two distinct sets of
chiral solutions with negative and positive parities, respectively, are found
in the nucleus 106Rh. The negative-parity solutions reproduce well the
corresponding experimental spectrum as well as the B(M1)/B(E2) ratios of the
transition strengths. This indicates that a predicted positive-parity chiral
band should also exist. Therefore, it provides a further strong hint that
multiple chirality is realized in nuclei.Comment: 15 pages, 5 figures, 1 tabl
Variational-Iterative Solution of Ground State for Central Potential
The newly developed iterative method based on Green function defined by
quadratures along a single trajectory is combined with the variational method
to solve the ground state quantum wave function for central potentials. As an
example, the method is applied to discuss the ground state solution of Yukawa
potential, using Hulthen solution as the trial function.Comment: 9 pages with 1 tabl
Detecting relic gravitational waves in the CMB: A statistical bias
Analyzing the imprint of relic gravitational waves (RGWs) on the cosmic
microwave background (CMB) power spectra provides a way to determine the signal
of RGWs. In this Letter, we discuss a statistical bias, which could exist in
the data analysis and has the tendency to overlook the RGWs. We also explain
why this bias exists, and how to avoid it.Comment: 4 pages, 1 figur
A Generalization of Mathieu Subspaces to Modules of Associative Algebras
We first propose a generalization of the notion of Mathieu subspaces of
associative algebras , which was introduced recently in [Z4] and
[Z6], to -modules . The newly introduced notion in a
certain sense also generalizes the notion of submodules. Related with this new
notion, we also introduce the sets and of stable elements
and quasi-stable elements, respectively, for all -subspaces of -modules , where is the base ring of . We then
prove some general properties of the sets and .
Furthermore, examples from certain modules of the quasi-stable algebras [Z6],
matrix algebras over fields and polynomial algebras are also studied.Comment: A new case has been added; some mistakes and misprints have been
corrected. Latex, 31 page
The mass estimate in narrow-line Seyfert 1 galaxies
It is possible that narrow-line Seyfert 1 galaxies (NLS1s) are in the early
stage of active galactic nuclei (AGNs) evolution. It is important to estimate
the mass of supermassive black hole (SBH) in NLS1s. Here we considered the
different kinds of methods to estimate the SBH masses in NLS1s. The virial mass
from the H linewidth assuming random orbits of broad line regions (BLRs)
is consistent with that from the statured soft X-ray luminosity, which showed
that most of NLS1s are in the super-Eddington accretion state. The mass from
the [O III] linewidth is systematically larger than that from above two
methods. It is necessary to measure he bulge stellar dispersion and/or bulge
luminosity in NLS1s.Comment: 2 Pages, 1 figure, in Prof. IAU Symposium No. 222, "The interplay
among Black Holes, Stars and ISM in Galactic Nuclei ", eds. T.
Storchi-Bergmann, Luis Ho and H. R. Schmit
An optimal factor analysis approach to improve the wavelet-based image resolution enhancement techniques
The existing wavelet-based image resolution enhancement techniques have many assumptions, such as limitation of the way to generate low-resolution images and the selection of wavelet functions, which limits their applications in different fields. This paper initially identifies the factors that effectively affect the performance of these techniques and quantitatively evaluates the impact of the existing assumptions. An approach called Optimal Factor Analysis employing the genetic algorithm is then introduced to increase the applicability and fidelity of the existing methods. Moreover, a new Figure of Merit is proposed to assist the selection of parameters and better measure the overall performance. The experimental results show that the proposed approach improves the performance of the selected image resolution enhancement methods and has potential to be extended to other methods
Matching the Quasi Parton Distribution in a Momentum Subtraction Scheme
The quasi parton distribution is a spatial correlation of quarks or gluons
along the direction in a moving nucleon which enables direct lattice
calculations of parton distribution functions. It can be defined with a
nonperturbative renormalization in a regularization independent momentum
subtraction scheme (RI/MOM), which can then be perturbatively related to the
collinear parton distribution in the scheme. Here we
carry out a direct matching from the RI/MOM scheme for the quasi-PDF to the
PDF, determining the non-singlet quark matching
coefficient at next-to-leading order in perturbation theory. We find that the
RI/MOM matching coefficient is insensitive to the ultraviolet region of
convolution integral, exhibits improved perturbative convergence when
converting between the quasi-PDF and PDF, and is consistent with a quasi-PDF
that vanishes in the unphysical region as the proton momentum ,
unlike other schemes. This direct approach therefore has the potential to
improve the accuracy for converting quasi-distribution lattice calculations to
collinear distributions.Comment: 18 pages, 6 figure
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