516 research outputs found
Note on Dirac--K\"ahler massless fields
We obtain the canonical and symmetrical Belinfante energy-momentum tensors of
Dirac--K\"{a}hler's fields. It is shown that the traces of the energy-momentum
tensors are not equal to zero. We find the canonical and Belinfante dilatation
currents which are not conserved, but a new conserved dilatation current is
obtained. It is pointed out that the conformal symmetry is broken. The
canonical quantization is performed and the propagator of the massless fields
in the first-order formalism is found.Comment: 16 pages, minor corrections in the text, published versio
Stabilization of a light bullet in a layered Kerr medium with sign-changing nonlinearity
Using the numerical solution of the nonlinear Schr\"odinger equation and a
variational method it is shown that (3+1)-dimensional spatiotemporal optical
solitons, known as light bullets, can be stabilized in a layered Kerr medium
with sign-changing nonlinearity along the propagation direction.Comment: 4 pages, 3 PS figure
The Modern Literary Process as a Factor of the Socialization and Integration of Russia and China (On the Example of the III Forum of Young Writers of China and Russia)
The article is devoted to the historical analysis of the socializing and integrating role of literature and the justification of the need for systemic socialization management by the state. The thesis on the use of literature as a factor in the state ideology formation in our days is proved. The role of Soviet literature as an important tool of political socialization is revealed, its significant influence on the literary process and the formation of state ideology in China is emphasized. The dynamics of Russian-Chinese relations is considered in connection with the transformation of the literary process of the both countries. The modern stage of literary and political integration is considered on the example of the III Forum of young writers of China and Russia (Shanghai, 2019). The interpretation of the main Forum’s cooperation vectors and relevant topics is based on the experience of direct participation in the work of the Forum of one of the article authors. The conclusion is drawn about the integration potential of modern literature, its focus on the restoration of the traditional values of Russian and Chinese cultures, their interpenetration and optimal coexistence
Noncommutative Electrodynamics
In this paper we define a causal Lorentz covariant noncommutative (NC)
classical Electrodynamics. We obtain an explicit realization of the NC theory
by solving perturbatively the Seiberg-Witten map. The action is polynomial in
the field strenght , allowing to preserve both causality and Lorentz
covariance. The general structure of the Lagrangian is studied, to all orders
in the perturbative expansion in the NC parameter . We show that
monochromatic plane waves are solutions of the equations of motion to all
orders. An iterative method has been developed to solve the equations of motion
and has been applied to the study of the corrections to the superposition law
and to the Coulomb law.Comment: 13 pages, 2 figures, one reference adde
Charge Radii and Magnetic Polarizabilities of the Rho and K* Mesons in QCD String Theory
The effective action for light mesons in the external uniform static
electromagnetic fields was obtained on the basis of QCD string theory. We imply
that in the presence of light quarks the area law of the Wilson loop integral
is valid. The approximation of the Nambu-Goto straight-line string is used to
simplify the problem. The Coulomb-like short-range contribution which goes from
one-gluon exchange is also neglected. We do not take into account spin-orbital
and spin-spin interactions of quarks and observe the and mesons.
The wave function of the meson ground state is the Airy function. Using the
virial theorem we estimate the mean charge radii of mesons in terms of the
string tension and the Airy function zero. On the basis of the perturbative
theory, in the small external magnetic field we find the diamagnetic
polarizabilities of and mesons: , Comment: 22 pages, no figures, in LaTeX 2.09, typos correcte
Seiberg-Witten-type Maps for Currents and Energy-Momentum Tensors in Noncommutative Gauge Theories
We derive maps relating the currents and energy-momentum tensors in
noncommutative (NC) gauge theories with their commutative equivalents. Some
uses of these maps are discussed. Especially, in NC electrodynamics, we obtain
a generalization of the Lorentz force law. Also, the same map for anomalous
currents relates the Adler-Bell-Jackiw type NC covariant anomaly with the
standard commutative-theory anomaly. For the particular case of two dimensions,
we discuss the implications of these maps for the Sugawara-type energy-momentum
tensor.Comment: 14 pages, JHEP styl
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
Recent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
The Energy-Momentum Tensor in Noncommutative Gauge Field Models
We discuss the different possibilities of constructing the various
energy-momentum tensors for noncommutative gauge field models. We use Jackiw's
method in order to get symmetric and gauge invariant stress tensors--at least
for commutative gauge field theories. The noncommutative counterparts are
analyzed with the same methods. The issues for the noncommutative cases are
worked out.Comment: 11 pages, completed reference
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