39 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
Maxwell - Chern - Simons topologically massive gauge fields in the first-order formalism
We find the canonical and Belinfante energy-momentum tensors and their
nonzero traces. We note that the dilatation symmetry is broken and the
divergence of the dilatation current is proportional to the topological mass of
the gauge field. It was demonstrated that the gauge field possesses the `scale
dimensionality' d=1/2. Maxwell - Chern - Simons topologically massive gauge
field theory in 2+1 dimensions is formulated in the first-order formalism. It
is shown that 6x6-matrices of the relativistic wave equation obey the Duffin -
Kemmer - Petiau algebra. The Hermitianizing matrix of the relativistic wave
equation is given. The projection operators extracting solutions of field
equations for states with definite energy-momentum and spin are obtained. The
5x5-matrix Schrodinger form of the equation is derived after the exclusion of
non-dynamical components, and the quantum-mechanical Hamiltonian is obtained.
Projection operators extracting physical states in the Schrodinger picture are
found.Comment: 18 pages, correction in Ref. [5
Pair Production and Vacuum Polarization of Arbitrary Spin Particles with EDM and AMM
The exact solutions of the wave equation for arbitrary spin particles with
electric dipole and magnetic moments in the constant and uniform
electromagnetic field were found. The differential probability of pair
production of particles by an external electromagnetic field has been
calculated on the basis of the exact solutions. We have also estimated the
imaginary part of the constant and uniform electromagnetic field. The nonlinear
corrections to the Maxwell Lagrangian have been calculated taking into account
the vacuum polarization of arbitrary spin particles. The role of electric
dipole and magnetic moments of arbitrary spin particles in instability of the
vacuum is discussed.Comment: 18 pages, LaTeX, accepted for publication in Ann.Phys.(USA
On Possible Light-Torsion Mixing in Background Magnetic Field
The interaction of the light with propagating axial torsion fields in the
presence of an external magnetic field has been investigated. Axial torsion
fields appearing in higher derivative quantum gravity possess two states, with
spin one and zero, with different masses. The torsion field with spin-0 state
is a ghost that can be removed if its mass is infinite. We investigate the
possibility when the light mixes with the torsion fields resulting in the
effect of vacuum birefringence and dichroism. The expressions for ellipticity
and the rotation of light polarization axis depending on the coupling constant
and the external magnetic field have been obtained.Comment: 12 pages, title changed, shortened journal version, accepted in
Eur.Phys.J.
Pair Production of Arbitrary Spin Particles by Electromagnetic Fields
The exact solutions of the wave equation for arbitrary spin particles in the
field of the soliton-like electric impulse were obtained. The differential
probability of pair production of particles by electromagnetic fields has been
evaluated on the basis of the exact solutions. As a particular case, the
particle pair producing in the constant and uniform electric field were
studied.Comment: 13 pages, no figure
Effective Lagrangian at Cubic Order in Electromagnetic Fields and Vacuum Birefringence
The effective Lagrangian of electromagnetic fields at the cubic order in
field strength has been considered. This generalized Lagrangian is motivated by
electrodynamics on non-commutative spaces. We find the canonical and
symmetrical energy-momentum tensors and show that they possess non-zero traces.
The propagation of a linearly polarized laser beam in the external transverse
magnetic field is investigated. We evaluate the induced ellipticity which
allows us to obtain a constraint on parameters introduced from the PVLAS
experimental data.Comment: 10 pages, no figures, added note, published versio
Equivalence of partition functions for noncommutative U(1) gauge theory and its dual in phase space
Equivalence of partition functions for U(1) gauge theory and its dual in
appropriate phase spaces is established in terms of constrained hamiltonian
formalism of their parent action. Relations between the electric--magnetic
duality transformation and the (S) duality transformation which inverts the
strong coupling domains to the weak coupling domains of noncommutative U(1)
gauge theory are discussed in terms of the lagrangian and the hamiltonian
densities. The approach presented for the commutative case is utilized to
demonstrate that noncommutative U(1) gauge theory and its dual possess the same
partition function in their phase spaces at the first order in the
noncommutativity parameter \theta .Comment: 15 pages. Version to appear in JHE
Dirac quantization of noncommutative Abelian Proca field
Dirac formalism of Hamiltonian constraint systems is studied for the
noncommutative Abelian Proca field. It is shown that the system of constraints
are of second class in agreement with the fact that the Proca field is not
guage invariant. Then, the system of second class constraints is quantized by
introducing Dirac brackets in the reduced phase space.Comment: 12 pages, minor revisio
On the energy-momentum tensor in non-commutative gauge theories
We study the properties of the energy-momentum tensor in non-commutative
gauge theories by coupling them to a weak external gravitational field. In
particular, we show that the stress tensor of such a theory coincides exactly
with that derived from a theory where a Seiberg-Witten map has been implemented
(namely, the procedure is commutative). Various other interesting features are
also discussed.Comment: 3 page
Amplitudes With Different Helicity Configurations Of Noncommutative QED
The amplitudes of purely photonic and photon{2-fermion processes of non-
commutative QED (NCQED) are derived for different helicity configurations of
photons. The basic ingredient is the NCQED counterpart of Yang-Mills recursion
relations by means of Berends and Giele. The explicit solutions of recursion
relations for NCQED photonic processes with special helicity configurations are
presented.Comment: 23 pages, 2 figure