3,545 research outputs found
Describing the set of words generated by interval exchange transformation
Let be an infinite word over finite alphabet . We get combinatorial
criteria of existence of interval exchange transformations that generate the
word W.Comment: 17 pages, this paper was submitted at scientific council of MSU,
date: September 21, 200
Purcell effect in wire metamaterials
We study theoretically the enhancement of spontaneous emission in wire
metamaterials. We analyze the dependence of the Purcell factor dependence on
wire dielectric constant for both electric and magnetic dipole sources, and
find an optimal value of the dielectric constant for maximizing the Purcell
factor for the electric dipole. We obtain analytical expressions for the
Purcell factor and also provide estimates for the Purcell factor in realistic
structures operating in both microwave and optical spectral range.Comment: 15 pages, 7 figure
LCG MCDB -- a Knowledgebase of Monte Carlo Simulated Events
In this paper we report on LCG Monte Carlo Data Base (MCDB) and software
which has been developed to operate MCDB. The main purpose of the LCG MCDB
project is to provide a storage and documentation system for sophisticated
event samples simulated for the LHC collaborations by experts. In many cases,
the modern Monte Carlo simulation of physical processes requires expert
knowledge in Monte Carlo generators or significant amount of CPU time to
produce the events. MCDB is a knowledgebase mainly dedicated to accumulate
simulated events of this type. The main motivation behind LCG MCDB is to make
the sophisticated MC event samples available for various physical groups. All
the data from MCDB is accessible in several convenient ways. LCG MCDB is being
developed within the CERN LCG Application Area Simulation project
Geometrical Description of the Local Integrals of Motion of Maxwell-Bloch Equation
We represent a classical Maxwell-Bloch equation and related to it positive
part of the AKNS hierarchy in geometrical terms. The Maxwell-Bloch evolution is
given by an infinitesimal action of a nilpotent subalgebra of affine Lie
algebra on a Maxwell-Bloch phase space treated as a homogeneous
space of . A space of local integrals of motion is described using
cohomology methods. We show that hamiltonian flows associated to the
Maxwell-Bloch local integrals of motion (i.e. positive AKNS flows) are
identified with an infinitesimal action of an abelian subalgebra of the
nilpotent subalgebra on a Maxwell- Bloch phase space. Possibilities of
quantization and latticization of Maxwell-Bloch equation are discussed.Comment: 16 pages, no figures, plain TeX, no macro
Magnetic dipole radiation tailored by substrates: numerical investigation
Nanoparticles of high refractive index materials can possess strong magnetic
polarizabilities and give rise to artificial magnetism in the optical spectral
range. While the response of individual dielectric or metal spherical particles
can be described analytically via multipole decomposition in the Mie series,
the influence of substrates, in many cases present in experimental
observations, requires different approaches. Here, the comprehensive numerical
studies of the influence of a substrate on the spectral response of high- index
dielectric nanoparticles were performed. In particular, glass, perfect electric
conductor, gold, and hyperbolic metamaterial substrates were investigated.
Optical properties of nanoparticles were characterized via scattering
cross-section spectra, electric field profiles, and induced electric and
magnetic moments. The presence of substrates was shown to introduce significant
impact on particle's magnetic resonances and resonant scattering
cross-sections. Variation of substrate material provides an additional degree
of freedom in tailoring properties of emission of magnetic multipoles,
important in many applications.Comment: 10 page, 28 figure
Toda lattice field theories, discrete W algebras, Toda lattice hierarchies and quantum groups
In analogy with the Liouville case we study the Toda theory on the
lattice and define the relevant quadratic algebra and out of it we recover the
discrete algebra. We define an integrable system with respect to the
latter and establish the relation with the Toda lattice hierarchy. We compute
the the relevant continuum limits. Finally we find the quantum version of the
quadratic algebra.Comment: 12 pages, LaTe
Long-period cosmic ray variations and their altitude dependence
Long-period variations were studied from the data of ground-based cosmic ray (CR) observations. In spite of a large value of an 2-year variation, it is more difficult to obtain its spectrum than the spectrum of a solar diurnal variation. Serious obstacles are caused by changes in individual detectors and in the whole world wide network of CR detectors, by the absence of continuity and uniformity of data series, by various apparatus variations. In discrimination and investigation of long-period variations an important and determining point is preparation and preliminary analysis of data
Engineered Optical Nonlocality in Nanostructured Metamaterials
We analyze dispersion properties of metal-dielectric nanostructured
metamaterials. We demonstrate that, in a sharp contrast to the results for the
corresponding effective medium, the structure demonstrates strong optical
nonlocality due to excitation of surface plasmon polaritons that can be
engineered by changing a ratio between the thicknesses of metal and dielectric
layers. In particular, this nonlocality allows the existence of an additional
extraordinary wave that manifests itself in the splitting of the TM-polarized
beam scattered at an air-metamaterial interface
The evolution operator of the Hartree-type equation with a quadratic potential
Based on the ideology of the Maslov's complex germ theory, a method has been
developed for finding an exact solution of the Cauchy problem for a
Hartree-type equation with a quadratic potential in the class of
semiclassically concentrated functions. The nonlinear evolution operator has
been obtained in explicit form in the class of semiclassically concentrated
functions. Parametric families of symmetry operators have been found for the
Hartree-type equation. With the help of symmetry operators, families of exact
solutions of the equation have been constructed. Exact expressions are obtained
for the quasi-energies and their respective states. The Aharonov-Anandan
geometric phases are found in explicit form for the quasi-energy states.Comment: 23 pege
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