91 research outputs found
Exact Solutions of Classical Electrodynamics and the Yang--Mills--Wong Theory in Even-Dimensional Spacetime
Exact solutions of classical gauge theories in even-dimensional (D=2n)
spacetimes are discussed. Common and specific properties of these solutions are
analyzed for the particular dimensions D=2, D=4, and D=6. A consistent
formulation of classical gauge field theories with pointlike charged or colored
particles is proposed for D=6. The particle Lagrangian must then depend on the
acceleration. The self-interaction of a point particle is considered for D=2
and D=6. In D=2, radiation is absent and all processes are reversible. In D=6,
the expression for the radiation rate and the equation of motion of a
self-interacting particle are derived; from which follows that the
Zitterbewegung always leads to radiation. It is shown that non-Abelian
solutions are absent for any D not equal to 4; only Coulomb-like solutions,
which correspond to the Abelian limit of the D-dimensional Yang--Mills--Wong
theory, are admitted.Comment: LaTeX 2.09, 16 page
Probability of Incipient Spanning Clusters in Critical Square Bond Percolation
The probability of simultaneous occurence of at least k spanning clusters has
been studied by Monte Carlo simulations on the 2D square lattice at the bond
percolation threshold . It is found that the probability of k and more
Incipient Spanning Clusters (ISC) has the values
and provided that the limit of these
probabilities for infinite lattices exists. The probability of more
than three ISC could be estimated to be of the order of 10^{-11} and is beyond
the possibility to compute a such value by nowdays computers. So, it is
impossible to check in simulations the Aizenman law for the probabilities when
. We have detected a single sample with 4 ISC in a total number of about
10^{10} samples investigated. The probability of single event is 1/10 for that
number of samples.Comment: 7 pages, 1 table, 5 figures (1PS+4*Latex),uses epsf.sty
Int.J.Mod.Phys. C (submitted to
Properties of electrons scattered on a strong plane electromagnetic wave with a linear polarization: classical treatment
The relations among the components of the exit momenta of ultrarelativistic
electrons scattered on a strong electromagnetic wave of a low (optical)
frequency and linear polarization are established using the exact solutions to
the equations of motion with radiation reaction included (the Landau-Lifshitz
equation). It is found that the momentum components of the electrons traversed
the electromagnetic wave depend weakly on the initial values of the momenta.
These electrons are mostly scattered at the small angles to the direction of
propagation of the electromagnetic wave. The maximum Lorentz factor of the
electrons crossed the electromagnetic wave is proportional to the work done by
the electromagnetic field and is independent of the initial momenta. The
momentum component parallel to the electric field strength vector of the
electromagnetic wave is determined only by the diameter of the laser beam
measured in the units of the classical electron radius. As for the reflected
electrons, they for the most part lose the energy, but remain relativistic.
There is a reflection law for these electrons that relates the incident and the
reflection angles and is independent of any parameters.Comment: 12 pp, 3 fig
Radiation reaction for multipole moments
We propose a Poincare-invariant description for the effective dynamics of
systems of charged particles by means of intrinsic multipole moments. To
achieve this goal we study the effective dynamics of such systems within two
frameworks -- the particle itself and hydrodynamical one. We give a
relativistic-invariant definition for the intrinsic multipole moments both
pointlike and extended relativistic objects. Within the hydrodynamical
framework we suggest a covariant action functional for a perfect fluid with
pressure. In the case of a relativistic charged dust we prove the equivalence
of the particle approach to the hydrodynamical one to the problem of radiation
reaction for multipoles. As the particular example of a general procedure we
obtain the effective model for a neutral system of charged particles with
dipole moment.Comment: 12 pages, 1 figure, RevTeX 4; references updated, minor textual
correction
Electrospray Ionization with High-Resolution Mass Spectrometry as a Tool for Lignomics: Lignin Mass Spectrum Deconvolution
Capability to characterize lignin, lignocellulose, and their degradation products is essential for development of new renewable feedstocks. Electrospray ionization high-resolution time-offlight mass spectrometry (ESI HR TOF MS) method was developed expanding the lignomics toolkit while targeting the simultaneous detection of low and high molecular weight (MW) lignin species. The effect of a broad range of electrolytes and various ionization conditions on ion formation and ionization effectiveness was studied using a suite of mono-, di- and triarene lignin model compounds as well as intact lignin. Contrary to the previous studies, the positive ionization mode was found to be more effective for methoxy-substituted arenes and polyphenols, i.e., species of a broadly varied MW structurally similar to the native lignin. For the first time, we report an effective formation of multiply charged species of lignin with the subsequent mass spectrum deconvolution in the presence of 100 mmol·L-1 formic acid in the positive ESI mode. The developed method enabled the detection of lignin species with an MW between 150 and 9,000 Da or higher, depending on the mass analyzer. The obtained Mn and Mw values of 1,500 and 2,500 Da, respectively, were in good agreement with those determined by gel permeation chromatography. Furthermore, the deconvoluted ESI mass spectrum was similar to that obtained with matrixassisted laser desorption/ionization (MALDI) TOF MS, yet featuring a higher signal-to-noise ratio. The formation of multiply charged species was confirmed with ESI ion mobility HR Q-TOF MS
From least action in electrodynamics to magnetomechanical energy -- a review
The equations of motion for electromechanical systems are traced back to the
fundamental Lagrangian of particles and electromagnetic fields, via the Darwin
Lagrangian. When dissipative forces can be neglected the systems are
conservative and one can study them in a Hamiltonian formalism. The central
concepts of generalized capacitance and inductance coefficients are introduced
and explained. The problem of gauge independence of self-inductance is
considered. Our main interest is in magnetomechanics, i.e. the study of systems
where there is exchange between mechanical and magnetic energy. This throws
light on the concept of magnetic energy, which according to the literature has
confusing and peculiar properties. We apply the theory to a few simple
examples: the extension of a circular current loop, the force between parallel
wires, interacting circular current loops, and the rail gun. These show that
the Hamiltonian, phase space, form of magnetic energy has the usual property
that an equilibrium configuration corresponds to an energy minimum.Comment: 29 pages, 9 figures, 65 reference
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