1,418 research outputs found
Stability of smooth solitary waves for the generalized Korteweg - de Vries equation with combined dispersion
The orbital stability problem of the smooth solitary waves in the generalized Korteweg - de Vries equation with combined dispersion is considered. The results show that the smooth solitary waves are stable for an arbitrary speed of wave propagation.Розглянуто задачу про орбітальну стійкість гладких відокремлених хвиль для узагальненого рівняння Кортевега – де Фріза з комбінованою дисперсією. Отримані результати показують, що гладкі відокремлені хвилі є стійкими при довільній швидкості поширення хвиль
R-parity violation effect on the top-quark pair production at linear colliders
We investigate in detail the effects of the R-parity lepton number violation
in the minimal supersymmetric standard model (MSSM) on the top-quark pair
production via both and collision modes at the linear
colliders. We find that with the present experimental constrained
parameters, the effect from interactions on the processes
and could be
significant and may reach -30% and several percent, respectively. Our results
show that the effects are sensitive to the c.m.s. energy and the
relevant parameters. However, they are not sensitive to squark and
slepton masses when (or ) and are almost independent on the Comment: Accepted by Phys.Rev.
Multiobjective Local Search Techniques for Evolutionary Polygonal Approximation
Proceedings of: 10th International Symposium on Distributed Computing and Artificial Intelligence . University of Salamanca (DCAI 2013). Salamanca, Spain, Spain, May 22-24, 2013.Polygonal approximation is based on the division of a closed curve into a set of segments. This problem has been traditionally approached as a single-objective optimization issue where the representation error was minimized according to a set of restrictions and parameters. When these approaches try to be subsumed into more recent multi-objective ones, a number of issues arise. Current work successfully adapts two of these traditional approaches and introduces them as initialization procedures for a MOEA approach to polygonal approximation, being the results, both for initial and final fronts, analyzed according to their statistical significance over a set of traditional curves from the domain.This work was supported in part by Projects MEyC TEC2012-37832-C02-01, MEyC TEC2011-28626-C02-02 and CAM CONTEXTS (S2009/TIC-1485).Publicad
Competing effects of mass anisotropy and spin Zeeman coupling on the upper critical field of a mixed - and s-wave superconductor
Based on the linearized Eilenberger equations, the upper critical field
of mixed d- and s-wave superconductors has been microscopically
studied with an emphasis on the competing effects of mass anisotropy and spin
Zeeman coupling. We find the mass anisotropy always enhance while the
Zeeman interaction suppresses . As required by the thermodynamics, we
find is saturated at zero temperature. We compare the theoretical
calculations with recent experimental data of
YBaCuO.Comment: To appear in PRB in Feb. 200
A Mechanism-Based Explanation of the Institutionalization of Semantic Technologies in the Financial Industry
Part 3: Creating Value through ApplicationsInternational audienceThis paper explains how the financial industry is solving its data, risk management, and associated vocabulary problems using semantic technologies. The paper is the first to examine this phenomenon and to identify the social and institutional mechanisms being applied to socially construct a standard common vocabulary using ontology-based models. This standardized ontology-based common vocabulary will underpin the design of next generation of semantically-enabled information systems (IS) for the financial industry. The mechanisms that are helping institutionalize this common vocabulary are identified using a longitudinal case study, whose embedded units of analysis focus on central agents of change—the Enterprise Data Management Council and the Object Management Group. All this has important implications for society, as it is intended that semantically-enabled IS will, for example, provide stakeholders, such as regulators, with better transparency over systemic risks to national and international financial systems, thereby mitigating or avoiding future financial crises
Properties of a Dilute Bose Gas near a Feshbach Resonance
In this paper, properties of a homogeneous Bose gas with a Feshbach resonance
are studied in the dilute region at zero temperature. The stationary state
contains condensations of atoms and molecules. The ratio of the molecule
density to the atom density is . There are two types of excitations,
molecular excitations and atomic excitations. Atomic excitations are gapless,
consistent with the traditional theory of a dilute Bose gas. The molecular
excitation energy is finite in the long wavelength limit as observed in recent
experiments on Rb. In addition, the decay process of the condensate is
studied. The coefficient of the three-body recombination rate is about 140
times larger than that of a Bose gas without a Feshbach resonance, in
reasonably good agreement with the experiment on Na.Comment: 11 pages, 1 figure, comparison between the calculated three-body
recombination rate and the experimental data for Na system has been adde
Matrix Model and Time-like Linear Dilaton Matter
We consider a matrix model description of the 2d string theory whose matter
part is given by a time-like linear dilaton CFT. This is equivalent to the c=1
matrix model with a deformed, but very simple fermi surface. Indeed, after a
Lorentz transformation, the corresponding 2d spacetime is a conventional linear
dilaton background with a time-dependent tachyon field. We show that the tree
level scattering amplitudes in the matrix model perfectly agree with those
computed in the world-sheet theory. The classical trajectories of fermions
correspond to the decaying D-branes in the time-like linear dilaton CFT. We
also discuss the ground ring structure. Furthermore, we study the properties of
the time-like Liouville theory by applying this matrix model description. We
find that its ground ring structure is very similar to that of the minimal
string.Comment: 30 pages, harvmac, typos corrected, acknowledgements and comments
added(v2), published version (v3
The rare top quark decays in the topcolor-assisted technicolor model
We consider the rare top quark decays in the framework of topcolor-assisted
technicolor (TC2) model. We find that the contributions of top-pions and
top-Higgs predicted by the TC2 model can enhance the SM branching ratios by as
much as 6-9 orders of magnitude. i.e., in the most case, the orders of
magnitude of branching ratios are , , . With the reasonable values of the
parameters in TC2 model, such rare top quark decays may be testable in the
future experiments. So, rare top quark decays provide us a unique way to test
TC2 model.Comment: 14 pages, 4 figure
Optical properties and radiative forcing of urban aerosols in Nanjing, China
AbstractContinuous measurements of atmospheric aerosols were made in Nanjing, a megacity in China, from 18 January to 18 April, 2011 (Phase 1) and from 22 April 2011 to 21 April 2012 (Phase 2). Aerosol characteristics, optical properties, and direct radiative forcing (DRF) were studied through interpretations of these measurements. We found that during Phase 1, mean PM2.5, black carbon (BC), and aerosol scattering coefficient (Bsp) in Nanjing were 76.1 ± 59.3 μg m−3, 4.1 ± 2.2 μg m−3, and 170.9 ± 105.8 M m−1, respectively. High pollution episodes occurred during Spring and Lantern Festivals when hourly PM2.5 concentrations reached 440 μg m−3, possibly due to significant discharge of fireworks. Temporal variations of PM2.5, BC, and Bsp were similar to each other. It is estimated that inorganic scattering aerosols account for about 49 ± 8.6% of total aerosols while BC only accounted for 6.6 ± 2.9%, and nitrate was larger than sulfate. In Phase 2, optical properties of aerosols show great seasonality. High relative humidity (RH) in summer (June, July, August) likely attributed to large optical depth (AOD) and small Angstrom exponent (AE) of aerosols. Due to dust storms, AE of total aerosols was the smallest in spring (March, April, May). Annual mean 550-nm AOD and 675/440-nm AE were 0.6 ± 0.3 and 1.25 ± 0.29 for total aerosols, 0.04 ± 0.02 and 1.44 ± 0.50 for absorbing aerosols, 0.48 ± 0.29 and 1.64 ± 0.29 for fine aerosols, respectively. Annual single scattering albedo of aerosols ranged from 0.90 to 0.92. Real time wavelength-dependent surface albedo from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to assess aerosol DRFs. Both total and absorbing aerosol DRFs had significant seasonal variations in Nanjing and they were the strongest in summer. Annual mean clear sky TOA DRF (including daytime and nighttime) of total and absorbing aerosols was about −6.9 and +4.5 W m−2, respectively. Aerosol DRFs were found to be sensitive to surface albedo. Over brighter surfaces, solar radiation was more absorbed by absorbing aerosols and less scattered by scattering aerosols
Spiral phase and phase separation of the double exchange model in the large-S limit
The phase diagram of the double exchange model is studied in the large-S
limit at zero temperature in two and three dimensions. We find that the spiral
state has lower energy than the canted antiferromagnetic state in the region
between the antiferromagnetic phase and the ferromagnetic phase. At small
doping, the spiral phase is unstable against phase separation due to its
negative compressibility. When the Hund coupling is small, the system separates
into spiral regions and antiferromagnetic regions. When the Hund coupling is
large, the spiral phase disappears completely and the system separates into
ferromagnetic regions and antiferromagnetic regions.Comment: 7 pages, 3 postscript figures. To be published in Phys. Rev.
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