3,196 research outputs found
Characteristics of synchrotron radiation of longitudinally polarized spinning particle in the pseudoclassical theory
Spin dependencies of the intensity and polarization of the synchrotron
radiation of the longitudinally polarized particle performing uniform circular
motion in the magnetic field are investigated.Comment: LATEX, 6 pages, misprints correcte
Pseudoclassical neutrino in the external electromagnetic field
The problem of the passage of the neutral massless particle with anomalous
magnetic moment through the external electromagnetic field is considered both
in pseudoclassical and quantum mechanics. The quantum description uses the
hamiltonian in the Foldy--Wouthuysen representation, obtained from the
pseudoclassical hamiltonian of the massive charged particle with anomalous
magnetic moment in interaction with the external electromagnetic field using
Weyl quantization scheme.Comment: LATEX, 10 pages, no figure
Pseudoclassical and quantum theory of the D=2n dimensional relativistic spinning particle with anomalous "magnetic" moment in the external Yang-Mills field
The pseudoclassical hamiltonian and action of the dimensional Dirac
particle with anomalous magnetic moment interacting with the external
Yang-Mills field are found. The Bargmann-Michel-Telegdi equation of motion for
the Pauli-Lubanski vector is deduced. The canonical quantization of
dimensional Dirac spinning particle with anomalous magnetic moment in the
external Yang-Mills field is carried out in the gauge which allows to describe
simultaneously particles and antiparticles (massive and massless) already at
the classical level. Pseudoclassical Foldy-Wouthuysen transformation is used to
obtain canonical (Newton-Wigner) coordinates and in terms of these variables
the theory is quantized.Comment: 10 pages, latex fil
About dual two-dimensional oscillator and Coulomb-like theories on a plane
We present a mathematically rigorous quantum-mechanical treatment of a
two-dimensional nonrelativistic quantum dual theories (with oscillator and
Coulomb like potentials) on a plane and compare their spectra and the sets of
eigenfunctions. All self-adjoint Schrodinger operators for these theories are
constructed and rigorous solutions of the corresponding spectral problems are
presented. The first part of the problem is solved by using a method of
specifying s.a. extensions by (asymptotic) s.a. boundary conditions. Solving
spectral problems, we follow the Krein's method of guiding functionals. We
show, that there is one to one correspondence between the spectral points of
dual theories in the planes energy-coupling constants not only for discrete,
but also for continuous spectra.Comment: 44 page
Pseudoclassical theory of Mayorana--Weyl particle
A pseudoclassical theory of Weyl particle in the space--time dimensions
is constructed. The canonical quantization of that pseudoclassical
theory is carried out and it results in the theory of the dimensional
Weyl particle in the Foldy--Wouthuysen representation. A quantum mechanics of
the neutral Weyl particle in even--dimensional space--time is suggested and the
connection of this theory with the theory of Mayorana--Weyl particle in QFT is
discussed for D=10.Comment: LATEX, 14 pages, no figures, replacement because of e-mail transfer
fault
Lienard-Wiechert potential and synchrotron radiation of a relativistic spinning particle in the pseudoclassical theory
Lienard-Wiechert potentials of the relativistic spinning particle with
anomalous magnetic moment in pseudoclassical theory are constructed. General
expressions for the Lienard-Wiechert potentials are used for investigation of
some specific cases of the motion of the spinning particle. In particular the
spin dependence of the intensity of the synchrotron radiation of the
transversely polarized particle performing uniform circular motion is
considered. When the movement of the particle in external homogeneous magnetic
field the obtained formulae coincide with those known from quantum theory of
radiation. The dependence of the polarization of the synchrotron radiation on
the spin of the particle is investigated.Comment: Latex, 15 pages, misprints corrected, reference adde
Structure and energetics of Ni clusters with up to 150 atoms
We present a method (the Aufbau/Abbau method) for optimizing the structure of
a whole series of clusters without making any assumptions on the structure.
Subsequently, the method is combined with the embedded-atom method in
determining the structure of the two energetically lowest isomers of Ni_N
clusters with N up to 150. Finally, various analytical descriptors are
introduced that are used in studying the overall shape of the clusters, their
structure and stability, and possible growth and dissociation processes.Comment: 16 pages, 5 figure
Theoretical study of structure and energetics of gold clusters with the EAM method
Using the Embedded Atom Method as developed by Voter and Chen in combination
with the {\it variable metric/quasi-Newton} and our own {\it Aufbau/Abbau}
methods, we have identified the three most stable isomers of Au clusters
with up to 150. For the first time clusters with tetrahedral symmetry are
found to form the ground states of Au and Au. The Au {\it
icosahedron} without a central atom and the Au {\it decahedron} are
found to be particularly stable, whereas the highly symmetric second and third
Mackay icosahedra that could have been obtained for = 55 and 147,
respectively, do not correspond to the particularly stable structures. The
three lowest-lying isomers of Au and Au are low-symmetrical
structures. Various structural and energetic properties are analysed, such as
stability function, occurrence of magic-sized clusters, construction of
icosahedral and {\it fcc} shells, and cluster growth.Comment: To appear in Z. Phys. Che
-dependence of coherent electroproduction of mesons on nuclei in forward direction
This article presents the -dependence of the differential cross section
for the coherent electroproduction of vector mesons on nuclei in forward
direction, at fixed values of longitudinal momentum transfer . It is
shown that such cross section has complicated behavior over the atomic mass
number with local minimums and maximums. It is also shown that a ratio of
the real to the imaginary parts of the forward coherent amplitude on nuclei
has breaking points at some values
of . Comparison of the behaviors of the normalized cross section
and over shows that the location of minimums of the cross
section are very close to the breaking points of
Adiabatic Transparency of Multilevel Atomic Media for Short High-intensity Pulses
We consider a medium of multilevel atomic systems interacting with radiation
pulses. A relatively simple technique of analytic calculations is proposed,
which allows revealing all necessary conditions (with sufficient conditions to
be checked separately) imposed on the interaction parameters, for which the
mean dipole moment of a multilevel atomic medium vanishes, i.e., the medium
becomes transparent via adiabatic interaction. The proposed technique is based
on the method of quasienergies and illustrated for three- and five-level atomic
systems. The necessary conditions for the propagation length where the
interaction adiabaticity is preserved in the medium are obtained
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