32,355 research outputs found
Sine-Gordon Soliton on a Cnoidal Wave Background
The method of Darboux transformation, which is applied on cnoidal wave
solutions of the sine-Gordon equation, gives solitons moving on a cnoidal wave
background. Interesting characteristics of the solution, i.e., the velocity of
solitons and the shift of crests of cnoidal waves along a soliton, are
calculated. Solutions are classified into three types (Type-1A, Type-1B,
Type-2) according to their apparent distinct properties.Comment: 11 pages, 5 figures, Contents change
Anomalous Height Fluctuation Width in Crossover from Random to Coherent Surface Growths
We study an anomalous behavior of the height fluctuation width in the
crossover from random to coherent growths of surface for a stochastic model. In
the model, random numbers are assigned on perimeter sites of surface,
representing pinning strengths of disordered media. At each time, surface is
advanced at the site having minimum pinning strength in a random subset of
system rather than having global minimum. The subset is composed of a randomly
selected site and its neighbors. The height fluctuation width
exhibits the non-monotonic behavior with and it has a
minimum at . It is found numerically that scales as
, and the height fluctuation width at that minimum,
, scales as in 1+1 dimensions. It is found that
the subset-size is the characteristic size of the crossover from
the random surface growth in the KPZ universality, to the coherent surface
growth in the directed percolation universality.Comment: 13 postscript file
Superconformal field theories from IIB spectroscopy on
We report on tests of the AdS/CFT correspondence that are made possible by
complete knowledge of the Kaluza-Klein mass spectrum of type IIB supergravity
on with T^{11}=SU(2)^2/U(1). After briefly discussing
general multiplet shortening conditions in SU(2,2|1) and PSU(2,2|4), we compare
various types of short SU(2,2|1) supermultiplets on AdS_5 and different
families of boundary operators with protected dimensions. The supergravity
analysis predicts the occurrence in the SCFT at leading order in N and g_s N,
of extra towers of long multiplets whose dimensions are rational but not
protected by supersymmetry.Comment: 11 pages, To appear in the proceedings of the STRINGS '99 conference,
Potsdam (Germany), 19-25 July 199
Total energy differences between SiC polytypes revisited
The total energy differences between various SiC polytypes (3C, 6H, 4H, 2H,
15R and 9R) were calculated using the full-potential linear muffin-tin orbital
method using the Perdew-Wang-(91) generalized gradient approximation to the
exchange-correlation functional in the density functional method. Numerical
convergence versus k-point sampling and basis set completeness are demonstrated
to be better than 1 meV/atom. The parameters of several generalized anisotropic
next-nearest-neighbor Ising models are extracted and their significance and
consequences for epitaxial growth are discussed.Comment: 8 pages, 3 figures, Latex, uses epsfig and revte
Multiexcitons confined within a sub-excitonic volume: Spectroscopic and dynamical signatures of neutral and charged biexcitons in ultrasmall semiconductor nanocrystals
The use of ultrafast gating techniques allows us to resolve both spectrally
and temporally the emission from short-lived neutral and negatively charged
biexcitons in ultrasmall (sub-10 nm) CdSe nanocrystals (nanocrystal quantum
dots). Because of forced overlap of electronic wave functions and reduced
dielectric screening, these states are characterized by giant interaction
energies of tens (neutral biexcitons) to hundreds (charged biexcitons) of meV.
Both types of biexcitons show extremely short lifetimes (from sub-100
picoseconds to sub-picosecond time scales) that rapidly shorten with decreasing
nanocrystal size. These ultrafast relaxation dynamics are explained in terms of
highly efficient nonradiative Auger recombination.Comment: 5 pages, 4 figures, to be published in Phys. Rev.
A Novel Dielectric Anomaly in Cuprates and Nickelates: Signature of an Electronic Glassy State
The low-frequency dielectric response of hole-doped insulators
La_{2}Cu_{1-x}Li_{x}O_{4} and La_{2-x}Sr_{x}NiO_{4} shows a large dielectric
constant \epsilon ^{'} at high temperature and a step-like drop by a factor of
100 at a material-dependent low temperature T_{f}. T_{f} increases with
frequency and the dielectric response shows universal scaling in a Cole-Cole
plot, suggesting that a charge glass state is realized both in the cuprates and
in the nickelates.Comment: 5 pages, 4 figure
Localization and Capacitance Fluctuations in Disordered Au Nano-junctions
Nano-junctions, containing atomic-scale gold contacts between strongly
disordered leads, exhibit different transport properties at room temperature
and at low temperature. At room temperature, the nano-junctions exhibit
conductance quantization effects. At low temperatures, the contacts exhibit
Coulomb-Blockade. We show that the differences between the room-temperature and
low temperature properties arise from the localization of electronic states in
the leads. The charging energy and capacitance of the nano-junctions exhibit
strong fluctuations with applied magnetic field at low temperature, as
predicted theoretically.Comment: 20 pages 8 figure
On higher dimensional Einstein spacetimes with a warped extra dimension
We study a class of higher dimensional warped Einstein spacetimes with one
extra dimension. These were originally identified by Brinkmann as those
Einstein spacetimes that can be mapped conformally on other Einstein
spacetimes, and have subsequently appeared in various contexts to describe,
e.g., different braneworld models or warped black strings. After clarifying the
relation between the general Brinkmann metric and other more specific
coordinate systems, we analyze the algebraic type of the Weyl tensor of the
solutions. In particular, we describe the relation between Weyl aligned null
directions (WANDs) of the lower dimensional Einstein slices and of the full
spacetime, which in some cases can be algebraically more special. Possible
spacetime singularities introduced by the warp factor are determined via a
study of scalar curvature invariants and of Weyl components measured by
geodetic observers. Finally, we illustrate how Brinkmann's metric can be
employed to generate new solutions by presenting the metric of spinning and
accelerating black strings in five dimensional anti-de Sitter space.Comment: 14 pages, minor changes in the text, mainly in Section 2.
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Getting it right: a model for compliance assessment
Compliance is important for organisations but models and tools to aid understanding of compliance behaviour is limited. This paper argues that the understanding of the interaction between subjects and objects and their intention to comply with requirements of rules and regulations may be a predictor of compliance behaviour. Thus, a Conceptual Compliance Assessment Model (CAM) is developed by extension of Technology Acceptance Model and Activity theory for assessment of compliance behaviour. Data collected and evaluated showed that the awareness and understanding of the mediational tool is critical in realizing the outcome. It also showed that other factors like the perceived usefulness, perceived ease of use, the community and the management set up also affected compliance behaviour. Essentially, the use of CAM will be useful in assessing the compliance activities of subjects which may aid in formulation of behaviour support systems to improve compliance behaviour
Learning 3D Human Pose from Structure and Motion
3D human pose estimation from a single image is a challenging problem,
especially for in-the-wild settings due to the lack of 3D annotated data. We
propose two anatomically inspired loss functions and use them with a
weakly-supervised learning framework to jointly learn from large-scale
in-the-wild 2D and indoor/synthetic 3D data. We also present a simple temporal
network that exploits temporal and structural cues present in predicted pose
sequences to temporally harmonize the pose estimations. We carefully analyze
the proposed contributions through loss surface visualizations and sensitivity
analysis to facilitate deeper understanding of their working mechanism. Our
complete pipeline improves the state-of-the-art by 11.8% and 12% on Human3.6M
and MPI-INF-3DHP, respectively, and runs at 30 FPS on a commodity graphics
card.Comment: ECCV 2018. Project page: https://www.cse.iitb.ac.in/~rdabral/3DPose
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