30,002 research outputs found
Gardner's deformations of the N=2 supersymmetric a=4-KdV equation
We prove that P.Mathieu's Open problem on constructing Gardner's deformation
for the N=2 supersymmetric a=4-Korteweg-de Vries equation has no supersymmetry
invariant solutions, whenever it is assumed that they retract to Gardner's
deformation of the scalar KdV equation under the component reduction. At the
same time, we propose a two-step scheme for the recursive production of the
integrals of motion for the N=2, a=4-SKdV. First, we find a new Gardner's
deformation of the Kaup-Boussinesq equation, which is contained in the bosonic
limit of the super-hierarchy. This yields the recurrence relation between the
Hamiltonians of the limit, whence we determine the bosonic super-Hamiltonians
of the full N=2, a=4-SKdV hierarchy. Our method is applicable towards the
solution of Gardner's deformation problems for other supersymmetric KdV-type
systems.Comment: Extended version of the talks given by A.V.K. at 8th International
conference `Symmetry in Nonlinear Mathematical Physics' (June 20-27, 2009,
Kiev, Ukraine) and 9th International workshop `Supersymmetry and Quantum
Symmetries' (July 29 - August 3, 2009, JINR, Dubna, Russia); 22 page
Correlation of normal and superconducting properties and unified approach to the description of high Tc oxides
We present a unified approach based on the Fermi liquid picture which allows us to describe the normal as well as the superconducting properties of the doped cuprates. The theory that is presented is for the doped compounds which are metallic. One can distinguish two interrelated, but nevertheless, different directions in the physics of high T(sub c): one involving the problem of carrier doping and the transition to the metallic state, and the second being the description of the metallic state. It is important that this metallic phase undergoes the transition into the superconducting state; as a result, our analysis is directly related to the origin of high T(sub c). We are using a quasi-2D Fermi liquid model to estimate the fundamental parameters of these very interesting materials. We find that this description is able to describe these materials and also that phonons and plasmons play a major role in the mechanism of high T(sub c)
Bose-Einstein Correlations in e+e- -> W+W- at a Linear Collider
We show that the most popular method to simulate Bose-Einstein (BE)
interference effects predicts negligible correlations between identical pions
originating from the hadronic decay of different W's produced in e+e- -> W+W-
-> 4 jets at typical linear collider energies.Comment: 5 pages, 2 eps figures, Proccedings of the Workshop "Physics Studies
for a Future Linear Collider", QCD Working Group, 2000, DESY 123
Investigation of the anisotropy of dissipation processes in single crystal of Yba2Cu3O7-d system
By means of contactless mechanical method of the measurement of energy losses
in superconductors, the anisotropy of dissipation processes has been studied in
single crystal high-temperature layered superconductors of Yba2Cu3O7-d system,
being in mixed state. The observed anisotropy of energy losses indicates the
possibility of the existence of the symmetry of order parameter of dx2-y2 type
in these single crystals.Comment: 4 pages, 3 figure
An Infinite Number of Closed FLRW Universes for Any Value of the Spatial Curvature
The Friedman-Lemaitre-Robertson-Walker (FLRW) cosmological models are based
on the assumptions of large-scale homogeneity and isotropy of the distribution
of matter and energy. They are usually taken to have spatial sections that are
simply connected; they have finite volume in the positive curvature case, and
infinite volume in the null and negative curvature ones. I want to call the
attention to the existence of an infinite number of models, which are based on
these same metrics, but have compact, finite volume, multiply connected spatial
sections. Some observational implications are briefly mentioned.Comment: 4 pages. Contribution to the 5th International Workshop on Astronomy
and Relativistic Astrophysics (Joao Pessoa, PB, Brazil, October 10-12, 2011)
and to the 1o. Simposio Jayme Tiomno (Brasilia, DF, Brazil, October 27-28,
2011). In version 2: a few minor corrections; two new references added. In
this version: title correction in Ref. 3; dedication paragraph at the en
Integrable quadratic Hamiltonians on so(4) and so(3,1)
We investigate a special class of quadratic Hamiltonians on so(4) and so(3,1)
and describe Hamiltonians that have additional polynomial integrals. One of the
main results is a new integrable case with an integral of sixth degree.Comment: 16 page
Collisions and drag in debris discs with eccentric parent belts
Context: High-resolution images of circumstellar debris discs reveal
off-centred rings that indicate past or ongoing perturbation, possibly caused
by secular gravitational interaction with unseen stellar or substellar
companions. The purely dynamical aspects of this departure from radial symmetry
are well understood. However, the observed dust is subject to additional forces
and effects, most notably collisions and drag. Aims: To complement the studies
of dynamics, we therefore aim to understand how new asymmetries are created by
the addition of collisional evolution and drag forces, and existing ones
strengthened or overridden. Methods: We augmented our existing numerical code
"Analysis of Collisional Evolution" (ACE) by an azimuthal dimension, the
longitude of periapse. A set of fiducial discs with global eccentricities
ranging from 0 to 0.4 is evolved over giga-year timescales. Size distribution
and spatial variation of dust are analysed and interpreted. The basic impact of
belt eccentricity on spectral energy distributions (SEDs) and images is
discussed.
Results: We find features imposed on characteristic timescales. First,
radiation pressure defines size cutoffs that differ between periapse and
apoapse, resulting in an asymmetric halo. The differences in size distribution
make the observable asymmetry of the halo depend on wavelength. Second,
collisional equilibrium prefers smaller grains on the apastron side of the
parent belt, reducing the effect of pericentre glow and the overall asymmetry.
Third, Poynting-Robertson drag fills the region interior to an eccentric belt
such that the apastron side is more tenuous. Interpretation and prediction of
the appearance in scattered light is problematic when spatial and size
distribution are coupled.Comment: Accepted for publication in A&A, 14 pages, 16 figure
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