200 research outputs found
Multi-Hamiltonian formulations and stability of higher-derivative extensions of Chern-Simons
Most general third-order linear gauge vector field theory is considered.
The field equations involve, besides the mass, two dimensionless constant
parameters. The theory admits two-parameter series of conserved tensors with
the canonical energy-momentum being a particular representative of the series.
For a certain range of the model parameters, the series of conserved tensors
include bounded quantities. This makes the dynamics classically stable, though
the canonical energy is unbounded in all the instances. The free third-order
equations are shown to admit constrained multi-Hamiltonian form with the
zero-zero components of conserved tensors playing the roles of corresponding
Hamiltonians. The series of Hamiltonians includes the canonical Ostrogradski's
one, which is unbounded. The Hamiltonian formulations with different
Hamiltonians are not connected by canonical transformations. This means, the
theory admits inequivalent quantizations at the free level. Covariant
interactions are included with spinor fields such that the higher-derivative
dynamics remains stable at interacting level if the bounded conserved quantity
exists in the free theory. In the first-order formalism, the interacting theory
remains Hamiltonian and therefore it admits quantization, though the vertices
are not necessarily Lagrangian in the third-order field equations.Comment: 19 page
Split Involution Coupled to Actual Gauge Symmetry
The split involution quantization scheme, proposed previously for pure
second--class constraints only, is extended to cover the case of the presence
of irreducible first--class constraints. The explicit Sp(2)--symmetry property
of the formalism is retained to hold. The constraint algebra generating
equations are formulated and the Unitarizing Hamiltonian is constructed.
Physical operators and states are defined in the sense of the new equivalence
criterion that is a natural counterpart to the Dirac's weak equality concept as
applied to the first--class quantities.Comment: 22pp, P.N.Lebedev Physical Institut
Radiation reaction and renormalization in classical electrodynamics of point particle in any dimension
The effective equations of motion for a point charged particle taking account
of radiation reaction are considered in various space-time dimensions. The
divergencies steaming from the pointness of the particle are studied and the
effective renormalization procedure is proposed encompassing uniformly the
cases of all even dimensions. It is shown that in any dimension the classical
electrodynamics is a renormalizable theory if not multiplicatively beyond d=4.
For the cases of three and six dimensions the covariant analogs of the
Lorentz-Dirac equation are explicitly derived.Comment: minor changes in concluding section, misprints corrected, LaTeX2e, 15
page
On the Minimal Model of Anyons
We present new geometric formulations for the fractional spin particle models
on the minimal phase spaces. New consistent couplings of the anyon to
background fields are constructed. The relationship between our approach and
previously developed anyon models is discussed.Comment: 17 pages, LaTex, no figure
Reducible Stueckelberg symmetry and dualities
We propose a general procedure for iterative inclusion of Stueckelberg fields
to convert the theory into gauge system being equivalent to the original one.
In so doing, we admit reducibility of the Stueckelberg gauge symmetry. In this
case, no pairing exists between Stueckelberg fields and gauge parameters,
unlike the irreducible Stueckelberg symmetry. The general procedure is
exemplified by the case of Proca model, with the third order involutive closure
chosen as the starting point. In this case, the set of Stueckelberg fields
includes, besides the scalar, also the second rank antisymmetric tensor. The
reducible Stueckelberg gauge symmetry is shown to admit different gauge fixing
conditions. One of the gauges reproduces the original Proca theory, while
another one excludes the original vector and the Stueckelberg scalar. In this
gauge, the irreducible massive spin one is represented by antisymmetric second
rank tensor obeying the third order field equations. Similar dual formulations
are expected to exist for the fields of various spins.Comment: 15 page
Restoring the full velocity field in the gaseous disk ofthe spiral galaxy NGC 157
We analyse the line-of-sight velocity field of ionized gas in the spiral
galaxy NGC 157 which has been obtained in the H\alpha emission at the 6m
telescope of SAO RAS. The existence of systematic deviations of the observed
gas velocities from pure circular motion is shown. A detailed investigation of
these deviations is undertaken by applying a Fourier analysis of the azimuthal
distributions of the line-of-sight velocities at different distances from the
galactic center. As a result of the analysis, all the main parameters of the
wave spiral pattern are determined: the corotation radius, the amplitudes and
phases of the gas velocity perturbations at different radii, and the velocity
of circular rotation of the disk corrected for the velocity perturbations due
to spiral arms. At a high confidence level, the presence of the two giant
anticyclones in the reference frame rotating with the spiral pattern is shown;
their sizes and the localization of their centers are consistent with the
results of the analytic theory and of numerical simulations. Besides the
anticyclones, the existence of cyclones in residual velocity fields of spiral
galaxies is predicted. In the reference frame rotating with the spiral pattern
these cyclones have to reveal themselves in galaxies where a radial gradient of
azimuthal residual velocity is steeper than that of the rotation velocity
(abridged).Comment: 23 pages including 25 eps-figures. Accepted for publication in A&
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