268,771 research outputs found
N-fold Parasupersymmetry
We find a new type of non-linear supersymmetries, called N-fold
parasupersymmetry, which is a generalization of both N-fold supersymmetry and
parasupersymmetry. We provide a general formulation of this new symmetry and
then construct a second-order N-fold parasupersymmetric quantum system where
all the components of N-fold parasupercharges are given by type A N-fold
supercharges. We show that this system exactly reduces to the
Rubakov-Spiridonov model when N=1 and admits a generalized type C 2N-fold
superalgebra. We conjecture the existence of other `N-fold generalizations'
such as N-fold fractional supersymmetry, N-fold orthosupersymmetry, and so on.Comment: 10 pages, no figures; Intro. expande
Properties and Curie Temperature (130 K) of Heavily Mn-doped Quaternary Alloy Ferromagnetic Semiconductor (InGaMn)As Grown on InP
We have studied magnetic properties of heavily Mn-doped
[(In0.44Ga0.56)0.79Mn0.21]As thin films grown by low-temperature molecular-beam
epitaxy (LT-MBE) on InP substrates. The (InGaMn)As with high Mn content (21%)
was obtained by decreasing the growth temperature to 190 degC. When the
thickness of the [(In0.44Ga0.56)0.79Mn0.21]As layer is equal or thinner than 10
nm, the reflection high-energy electron diffraction (RHEED) pattern and
transmission electron microscopy (TEM) show no MnAs clustering, indicating that
a homogeneous single crystal with good quality was grown. In the magnetic
circular dicroism (MCD) measurement, large MCD intensity and high Curie
temperature of 130 K were observed.Comment: 3 pages, 5 figure
Effects of disorder on conductance through small interacting systems
We study the effects of disorders on the transport through small interacting
systems based on a two-dimensional Hubbard cluster of finite size connected to
two noninteracting leads. This system can be regarded as a model for the
superlattice of quantum dots or atomic network of the nanometer size.
We calculate the conductance at T=0 using the order self-energy in an
electron-hole symmetric case. The results show that the conductance is ensitive
to the randomness when the resonance states are situated near the Fermi energy.Comment: 2 pages, 3 figures, to be published in Physica E, proceedings Low
Temperature Physics 23 (Hirosima, Japan
Strong consistency of the maximum likelihood estimator for finite mixtures of location-scale distributions when penalty is imposed on the ratios of the scale parameters
In finite mixtures of location-scale distributions, if there is no constraint
or penalty on the parameters, then the maximum likelihood estimator does not
exist because the likelihood is unbounded. To avoid this problem, we consider a
penalized likelihood, where the penalty is a function of the minimum of the
ratios of the scale parameters and the sample size. It is shown that the
penalized maximum likelihood estimator is strongly consistent. We also analyze
the consistency of a penalized maximum likelihood estimator where the penalty
is imposed on the scale parameters themselves.Comment: 29 pages, 2 figure
Practical Model Construction and Stable Control of an Unmanned Aerial Vehicle With a Parafoil-Type Wing
This correspondence paper presents a framework for practical model construction and stable altitude control of an unmanned aerial vehicle with a parafoil-type wing (UAV-PW). To design a stable controller, we first construct a dynamical longitudinal model of the UAV-PW. Since there exist no aerodynamics data of the parafoil shape in our UAV-PW, aerodynamics coefficients balanced at the trimmed equilibrium are employed. The model accuracy is investigated by comparing the model outputs with the real test flight experimental data. Next, stable controller design conditions for the UAV-PW model with uncertainties are derived in terms of linear matrix inequalities (LMIs). By solving the LMI conditions, we design a stable controller that asymptotically stabilizes the UAV-PW model with the uncertainties on a considered operation domain. The experimental results demonstrate the viability of the model construction and the stable altitude control
Transport through a single Anderson impurity coupled to one normal and two superconducting leads
We study the interplay between the Kondo and Andreev-Josephson effects in a
quantum dot coupled to one normal and two superconducting (SC) leads. In the
large gap limit, the low-energy states of this system can be described exactly
by a local Fermi liquid for the interacting Bogoliubov particles. The phase
shift and the renormalized parameters for the Bogoliubov particles vary
depending on the Josephson phase between the two SC leads. We explore the
precise features of a crossover that occurs between the Kondo singlet and local
Cooper-pairing states as the Josephson phase varies, using the numerical
renormalization group approach.Comment: 4 pages, 4 figures, contribution to SCES 201
Homogeneous SPC/E water nucleation in large molecular dynamics simulations
We perform direct large molecular dynamics simulations of homogeneous SPC/E
water nucleation, using up to molecules. Our large system
sizes allow us to measure extremely low and accurate nucleation rates, down to
, helping close the gap between
experimentally measured rates .
We are also able to precisely measure size distributions, sticking
efficiencies, cluster temperatures, and cluster internal densities. We
introduce a new functional form to implement the Yasuoka-Matsumoto nucleation
rate measurement technique (threshold method). Comparison to nucleation models
shows that classical nucleation theory over-estimates nucleation rates by a few
orders of magnitude. The semi-phenomenological nucleation model does better,
under-predicting rates by at worst, a factor of 24. Unlike what has been
observed in Lennard-Jones simulations, post-critical clusters have temperatures
consistent with the run average temperature. Also, we observe that
post-critical clusters have densities very slightly higher, , than
bulk liquid. We re-calibrate a Hale-type vs. scaling relation using
both experimental and simulation data, finding remarkable consistency in over
orders of magnitude in the nucleation rate range, and K in the
temperature range.Comment: Accepted for publication in the Journal of Chemical Physic
A Method to Extract the Structural Strata and Elements of Landscape Using GIS
Analyzing the landscape with using large three-dimensional database is well noted as the new method. In applying the method, the measure to divide the database into several densities of data to adjust many places and to analyze in mainframe computer is in need. The purpose of this study is to clarify the method of dividing spaces into structural layer, which can be measured in its quantity._ The theoretical method to extract the landscape elements by the distance from the viewpoint has been recognized by the previous studies, which based on the human phenomenon philosophy. However, the quantities of distance, which defines the space as a whole environment around viewpoint is not yet applicable for practical design. Because, the quantities have not been clearly found to apply to the real space since, feelings of distance varies by personal image. The cause of differences are due to some factors such as physical factors including the topography, the vegetation, and the building surroundings. Furthermore, there are other factors for example, psychological and social._ In this study, the physically caused distance definition is to be cleared through the method to extract the structural strata and the elements of landscape._ As an initial analysis, the angle of gaze from viewpoint, based on human engineering, the heights of the layers were examined and clearly found. The relationship between the eyesight and the angle of gaze are analyzed. Secondly, the continuity of figure from viewpoint are measured. It applied the fifty meters mesh digital map, the topographic vector data, the aerial photograph, and the building form vector data, to the Geographic Information System; the SIS and the ArcGIS. It proved that three scale of view; the close, the distance, and the background divides the real landscape. With this result, the method to extract the structural strata are found._ Preliminary, the methodsÕ application was tried to real spaces for further analysis. The results encouraged the analysis of physical quantity related with the human image including the time-space, and the relationship between the view and the other sense, which are under processes._
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