9,453 research outputs found
Crystal isomorphisms in Fock spaces and Schensted correspondence in affine type A
We are interested in the structure of the crystal graph of level Fock
spaces representations of . Since
the work of Shan [26], we know that this graph encodes the modular branching
rule for a corresponding cyclotomic rational Cherednik algebra. Besides, it
appears to be closely related to the Harish-Chandra branching graph for the
appropriate finite unitary group, according to [8]. In this paper, we make
explicit a particular isomorphism between connected components of the crystal
graphs of Fock spaces. This so-called "canonical" crystal isomorphism turns out
to be expressible only in terms of: - Schensted's classic bumping procedure, -
the cyclage isomorphism defined in [13], - a new crystal isomorphism, easy to
describe, acting on cylindric multipartitions. We explain how this can be seen
as an analogue of the bumping algorithm for affine type . Moreover, it
yields a combinatorial characterisation of the vertices of any connected
component of the crystal of the Fock space
Spherical-box approach for resonances in presence of Coulomb interaction
The spherical-box approach is extended to calculate the resonance parameters
and the real part of the wave function for single particle resonances in a
potential containing the long-range Coulomb interaction. A model potential is
taken to demonstrate the ability and accuracy of this approach. The calculated
resonance parameters are compared with available results from other methods. It
is shown that in the presence of the Coulomb interaction, the spherical-box
approach works well for not so broad resonances. In particular, for very narrow
resonances, the present method gives resonance parameters in a very high
precision.Comment: 10 pages, 5 EPS figures; to be published in J. Phys.
New effective interactions in RMF theory with non-linear terms and density-dependent meson-nucleon coupling
New parameter sets for the Lagrangian density in the relativistic mean field
(RMF) theory, PK1 with nonlinear sigma- and omega-meson self-coupling, PK1R
with nonlinear sigma-, omega- and rho-meson self-coupling and PKDD with the
density-dependent meson-nucleon coupling, are proposed. They are able to
provide an excellent description not only for the properties of nuclear matter
but also for the nuclei in and far from the valley of beta-stability. For the
first time in the parametrization of the RMF Lagrangian density, the
center-of-mass correction is treated by a microscopic way, which is essential
to unify the description of nuclei from light to heavy regions with one
effective interaction.Comment: 22 pages, 16 EPS figures, RevTeX
A Systematic Review of Studies Comparing the Measurement Properties of the Three-Level and Five-Level Versions of the EQ-5D
Background: Since the introduction of the five-level version of the EQ-5D (5L), many studies have comparatively investigated the measurement properties of the original three-level version (3L) with the 5L version.
Objective: The aim of this study was to consolidate the available evidence on the performance of both instruments. Methods: A systematic literature search of studies in the English and German languages was conducted (2007–January 2018) using the PubMed, EMBASE, and PsycINFO (EBSCO) databases, as well as the EuroQol Research Foundation website. Data were extracted and assessed on missing values, distributional properties, informativity indices (Shannon’s H′ and J′), inconsistencies, responsiveness, and test–retest reliability.
Results: Twenty-four studies were included in the review. Missing values and floor effects (percentage reporting the worst health state) were found to be negligible for both 3L and 5L (< 5%). From 18 studies, inconsistencies ranged from 0 to 10.6%, although they were generally well below 5%, with 9 studies reporting the most inconsistencies for Usual Activities (mean percentage 4.1%). Shannon’s indices were always higher for 5L than for 3L, and all but three studies reported lower ceiling effects (‘11111’) for 5L than for 3L. There is mixed and insufficient evidence on responsiveness and test–retest reliability, although results on index values showed better performance for 5L on test–retest reliability.
Conclusion: Overall, studies showed similar or better measurement properties of the 5L compared with the 3L, and evidence indicated moderately better distributional parameters and substantial improvement in informativity for the 5L compared with the 3L. Insufficient evidence on responsiveness and test–retest reliability implies further research is needed
Size-selective nanoparticle growth on few-layer graphene films
We observe that gold atoms deposited by physical vapor deposition onto few
layer graphenes condense upon annealing to form nanoparticles with an average
diameter that is determined by the graphene film thickness. The data are well
described by a theoretical model in which the electrostatic interactions
arising from charge transfer between the graphene and the gold particle limit
the size of the growing nanoparticles. The model predicts a nanoparticle size
distribution characterized by a mean diameter D that follows a scaling law D
proportional to m^(1/3), where m is the number of carbon layers in the few
layer graphene film.Comment: 15 pages, 4 figure
The dissipation of the system and the atom in two-photon Jaynes-Cummings model with degenerate atomic levels
The method of perturbative expansion of master equation is employed to study
the dissipative properties of system and of atom in the two-photon
Jaynes-Cummings model (JCM) with degenerate atomic levels. The numerical
results show that the degeneracy of atomic levels prolongs the period of
entanglement between the atom and the field. The asymptotic value of atomic
linear entropy is apparently increased by the degeneration. The amplitude of
local entanglement and disentanglement is suppressed. The better the initial
coherence property of the degenerate atom, the larger the coherence loss.Comment: 11 pages, 4 figure
Roles of moisture and cyclic loading in microstructures and their effects on mechanical properties for typical Chinese bituminous coals
This work aimed at studying the roles of moisture and cyclic loading in microstructures and their effects on mechanical properties for typical Chinese bituminous coals. Different relative moisture contents (100%, 75%, 50%, 25%, and 0%) for Shenmu coal (SM), Hongshaquan coal (HSQ), and Wucaiwan coal (WCW) were chosen to study the effects of moisture. The raw SM was then further selected to investigate the effects of cyclic loading. Images of coals surfaces and mechanical properties during simulated crushing process were recorded and combined to be analyzed. The results showed that the moisture possessed significant effects on coal mechanical properties, which strongly depended on their porosities. As for low porosity coal (SM), the adsorption of moisture can soften and lubricate the microstructures, weakening mechanical properties. While the drying process would destroy the microstructures and decease mechanical properties for high porosity coals (HSQ and WCW). Under the cyclic loading process, the cumulative effects of strain showed a step-up state and the first cyclic loading can typically cause the biggest change of microstructures and produce the largest strain under different stress levels. Finally, a normalized quantitative relationship ([fórmula]) between the relative fractal dimension and relative stress was built
Terahertz generation in Czochralski grown periodically poled Mg:Y:LiNbO3 via optical rectification
Using a canonical pump-probe experimental technique, we studied the terahertz
(THz) waves generation and detection via optical rectification and mixing in
Czochralski-grown periodically poled Mg:Y:LiNbO3 (PPLN) crystals. THz waves
with frequencies at 1.37 THz and 0.68 THz as well as 1.8 THz were obtained for
PPLN with nonlinear grating periods of 0.03 and 0.06 mm, respectively. A
general theoretical model was developed by considering the dispersion and
damping of low frequency phonon-polariton mode. Our results show that THz waves
are generated in forward and backward directions via pumping pulse
rectification. The generated THz waves depend on the spectral shape of the
laser pulses, quasi-phase mismatches and dispersion characteristics of a
crystal.Comment: 25 pages, 4 figure
Density-Matrix Renormalization-Group Analysis of Quantum Critical Points: I. Quantum Spin Chains
We present a simple method, combining the density-matrix
renormalization-group (DMRG) algorithm with finite-size scaling, which permits
the study of critical behavior in quantum spin chains. Spin moments and
dimerization are induced by boundary conditions at the chain ends and these
exhibit power-law decay at critical points. Results are presented for the
spin-1/2 Heisenberg antiferromagnet; an analytic calculation shows that
logarithmic corrections to scaling can sometimes be avoided. We also examine
the spin-1 chain at the critical point separating the Haldane gap and dimerized
phases. Exponents for the dimer-dimer and the spin-spin correlation functions
are consistent with results obtained from bosonization.Comment: 21 pages, 12 figures, new results and added references, to appear in
PR
- …