788 research outputs found
Soliton X-junctions with controllable transmission
We propose new planar X-junctions and multi-port devices written by spatial
solitons, which are composed of two (or more) nonlinearly coupled components in
Kerr-type media. Such devices have no radiation losses at a given wavelength.
We demonstrate that, for the same relative angle between the channels of the
X-junctions, one can vary the transmission coefficients into the output
channels by adjusting the polarizations of multi-component solitons. We
determine analytically the transmission properties and suggest two types of
experimental embodiments of the proposed device.Comment: 3 pages, 2 figure
Analytical solution of the dynamical spherical MIT bag
We prove that when the bag surface is allowed to move radially, the equations
of motion derived from the MIT bag Lagrangian with massless quarks and a
spherical boundary admit only one solution, which corresponds to a bag
expanding at the speed of light. This result implies that some new physics
ingredients, such as coupling to meson fields, are needed to make the dynamical
bag a consistent model of hadrons.Comment: Revtex, no figures. Submitted to Journal of Physics
Intensity limits for stationary and interacting multi-soliton complexes
We obtain an accurate estimate for the peak intensities of multi-soliton
complexes for a Kerr-type nonlinearity in the (1+1) - dimension problem. Using
exact analytical solutions of the integrable set of nonlinear Schrodinger
equations, we establish a rigorous relationship between the eigenvalues of
incoherently-coupled fundamental solitons and the range of admissible
intensities. A clear geometrical interpretation of this effect is given.Comment: 3 pages, 3 figure
Relativistic confinement of neutral fermions with a trigonometric tangent potential
The problem of neutral fermions subject to a pseudoscalar potential is
investigated. Apart from the solutions for , the problem is
mapped into the Sturm-Liouville equation. The case of a singular trigonometric
tangent potential () is exactly solved and the
complete set of solutions is discussed in some detail. It is revealed that this
intrinsically relativistic and true confining potential is able to localize
fermions into a region of space arbitrarily small without the menace of
particle-antiparticle production.Comment: 12 page
Study on the Prognosis of Tuberculous Meningitis Treated with Streptomycin in Children
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Multisoliton complexes in a sea of radiation modes
We derive exact analytical solutions describing multi-soliton complexes and
their interactions on top of a multi-component background in media with
self-focusing or self-defocusing Kerr-like nonlinearities. These results are
illustrated by numerical examples which demonstrate soliton collisions and
field decomposition between localized and radiation modes.Comment: 7 pages, 7 figure
Relating pseudospin and spin symmetries through charge conjugation and chiral transformations: the case of the relativistic harmonic oscillator
We solve the generalized relativistic harmonic oscillator in 1+1 dimensions,
i.e., including a linear pseudoscalar potential and quadratic scalar and vector
potentials which have equal or opposite signs. We consider positive and
negative quadratic potentials and discuss in detail their bound-state solutions
for fermions and antifermions. The main features of these bound states are the
same as the ones of the generalized three-dimensional relativistic harmonic
oscillator bound states. The solutions found for zero pseudoscalar potential
are related to the spin and pseudospin symmetry of the Dirac equation in 3+1
dimensions. We show how the charge conjugation and chiral
transformations relate the several spectra obtained and find that for massless
particles the spin and pseudospin symmetry related problems have the same
spectrum, but different spinor solutions. Finally, we establish a relation of
the solutions found with single-particle states of nuclei described by
relativistic mean-field theories with scalar, vector and isoscalar tensor
interactions and discuss the conditions in which one may have both nucleon and
antinucleon bound states.Comment: 33 pages, 10 figures, uses revtex macro
Enhancement of Sm3+emission by SnO2nanocrystals in the silica matrix
Silica xerogels containing Sm3+ions and SnO2nanocrystals were prepared in a solâgel process. The image of transmission electron microscopy (TEM) shows that the SnO2nanocrystals are dispersed in the silica matrix. The X-ray diffraction (XRD) of the sample confirms the tetragonal phase of SnO2. The xerogels containing SnO2nanocrystals and Sm3+ions display the characteristic emission of Sm3+ions (4G5/2 â 6HJ(J = 5/2, 7/2, 9/2)) at the excitation of 335 nm which energy corresponds to the energy gap of the SnO2nanocrystals, while no emission of Sm3+ions can be observed for the samples containing Sm3+ions. The enhancement of the Sm3+emission is probably due to the energy transfer from SnO2nanocrystals to Sm3+ions
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