319 research outputs found
Classical approach in quantum physics
The application of a classical approach to various quantum problems - the
secular perturbation approach to quantization of a hydrogen atom in external
fields and a helium atom, the adiabatic switching method for calculation of a
semiclassical spectrum of hydrogen atom in crossed electric and magnetic
fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's
approach to Stark problem, long-lived excited states of a helium atom recently
discovered with the help of Poincar section, inelastic
transitions in slow and fast electron-atom and ion-atom collisions - is
reviewed. Further, a classical representation in quantum theory is discussed.
In this representation the quantum states are treating as an ensemble of
classical states. This approach opens the way to an accurate description of the
initial and final states in classical trajectory Monte Carlo (CTMC) method and
a purely classical explanation of tunneling phenomenon. The general aspects of
the structure of the semiclassical series such as renormgroup symmetry,
criterion of accuracy and so on are reviewed as well. In conclusion, the
relation between quantum theory, classical physics and measurement is
discussed.Comment: This review paper was rejected from J.Phys.A with referee's comment
"The author has made many worthwhile contributions to semiclassical physics,
but this article does not meet the standard for a topical review"
General solution of equations of motion for a classical particle in 9-dimensional Finslerian space
A Lagrangian description of a classical particle in a 9-dimensional flat
Finslerian space with a cubic metric function is constructed. The general
solution of equations of motion for such a particle is obtained. The Galilean
law of inertia for the Finslerian space is confirmed.Comment: 10 pages, LaTeX-2e, no figures; added 2 reference
On foundations of quantum physics
Some aspects of the interpretation of quantum theory are discussed. It is
emphasized that quantum theory is formulated in the Cartesian coordinate
system; in other coordinates the result obtained with the help of the
Hamiltonian formalism and commutator relations between 'canonically conjugated'
coordinate and momentum operators leads to a wrong version of quantum
mechanics. The origin of time is analyzed in detail by the example of atomic
collision theory. It is shown that for a closed system like the three-body (two
nuclei + electron) time-dependent Schroedinger equation has no physical meaning
since in the high impact energy limit it transforms into an equation with two
independent time-like variables; the time appears in the stationary
Schroedinger equation as a result of extraction of a classical subsystem (two
nuclei) from a closed three-body system. Following the Einstein-Rozen-Podolsky
experiment and Bell's inequality the wave function is interpreted as an actual
field of information in the elementary form. The relation between physics and
mathematics is also discussed.Comment: This article is extended version of paper: Solov'ev, E.A.:
Phys.At.Nuc. v. 72, 853 (2009
Non-sequential double ionization below laser-intensity threshold: Anticorrelation of electrons without excitation of parent ion
Two-electron correlated spectra of non-sequential double ionization below
laser-intensity threshold are known to exhibit back-to-back scattering of the
electrons, viz., the anticorrelation of the electrons. Currently, the widely
accepted interpretation of the anticorrelation is recollision-induced
excitation of the ion plus subsequent field ionization of the second electron.
We argue that another mechanism, namely simultaneous electron emission, when
the time of return of the rescattered electron is equal to the time of
liberation of the bounded electron (the ion has no time for excitation), can
also explain the anticorrelation of the electrons in the deep below
laser-intensity threshold regime. Our conclusion is based on the results of the
numerical solution of the time-dependent Schr\"{o}dinger equation for a model
system of two one-dimensional electrons as well as an adiabatic analytic model
that allows for a closed-form solution.Comment: 6 pages and 3 figure
Free Boundary Poisson Bracket Algebra in Ashtekar's Formalism
We consider the algebra of spatial diffeomorphisms and gauge transformations
in the canonical formalism of General Relativity in the Ashtekar and ADM
variables. Modifying the Poisson bracket by including surface terms in
accordance with our previous proposal allows us to consider all local
functionals as differentiable. We show that closure of the algebra under
consideration can be achieved by choosing surface terms in the expressions for
the generators prior to imposing any boundary conditions. An essential point is
that the Poisson structure in the Ashtekar formalism differs from the canonical
one by boundary terms.Comment: 19 pages, Latex, amsfonts.sty, amssymb.st
Dynamics of quantum systems
A relation between the eigenvalues of an effective Hamilton operator and the
poles of the matrix is derived which holds for isolated as well as for
overlapping resonance states. The system may be a many-particle quantum system
with two-body forces between the constituents or it may be a quantum billiard
without any two-body forces. Avoided crossings of discrete states as well as of
resonance states are traced back to the existence of branch points in the
complex plane. Under certain conditions, these branch points appear as double
poles of the matrix. They influence the dynamics of open as well as of
closed quantum systems. The dynamics of the two-level system is studied in
detail analytically as well as numerically.Comment: 21 pages 7 figure
Hadronic Regge Trajectories: Problems and Approaches
We scrutinized hadronic Regge trajectories in a framework of two different
models --- string and potential. Our results are compared with broad spectrum
of existing theoretical quark models and all experimental data from PDG98. It
was recognized that Regge trajectories for mesons and baryons are not straight
and parallel lines in general in the current resonance region both
experimentally and theoretically, but very often have appreciable curvature,
which is flavor-dependent. For a set of baryon Regge trajectories this fact is
well described in the considered potential model. The standard string models
predict linear trajectories at high angular momenta J with some form of
nonlinearity at low J.Comment: 15 pages, 9 figures, LaTe
Characteristics of Phenotypic and Genetic Properties of <i>Francisella tularensis</i> 15 NIIEG Vaccine Strain with an Extended Storage Period
Investigated have been cultural-morphological, biochemical and genetic properties of lyophilized cultures of F. tularensis 15 NIIEG vaccine strain, accumulated within 60-years term and deposited at the State Collection of Pathogenic Microorganisms of Scientific Center on Expertise of Medical Application Products. The studies undertaken have demonstrated that storing of the strains in such a form at low temperatures, does not prevent changes of their genetic and phenotypic properties to the full extent. It is established that F. tularensis 15 NIIEG strain lyophilized in 1953, 1966, 1969, 2003 and 2012 maintains its immunogenic properties when cultivated on nutrient media Ft-agar with or without addition of blood, based on dissociation rates (87-99 %) of SR-colonies. While F. tularensis 15 NIIEG strain 1990 contains specified amounts (not less than 80 %) of immunogenic colonies if cultivated on nutrient media with the addition of blood, and fails to meet the requirements - if cultivated without. Identified in F. tularensis 15 NIIEG strain 1987 SR-colony decrement of 70-75 % in case of cultivation with or without addition of blood testifies to the deterioration of its immunogenic properties. RAPD and ERIC typing has showed high stability of the genome of F. tularensis 15 NIIEG cultures lyophilized at different times. Tularemia microbe vaccine strain has unique RAPD and ERIC profiles, insignificant alteration of which is observed upon storage of pathogen subculture in the dried from
Resonance scattering and singularities of the scattering function
Recent studies of transport phenomena with complex potentials are explained
by generic square root singularities of spectrum and eigenfunctions of
non-Hermitian Hamiltonians. Using a two channel problem we demonstrate that
such singularities produce a significant effect upon the pole behaviour of the
scattering matrix, and more significantly upon the associated residues. This
mechanism explains why by proper choice of the system parameters the resonance
cross section is increased drastically in one channel and suppressed in the
other channel.Comment: 4 pages, 3 figure
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