596 research outputs found
A 3-form Gauge Potential in 5D in connection with a Possible Dark Sector of 4D-Electrodynamics
We here propose a 5-dimensional {\bf Abelian gauge} model based on the mixing
between a potential and an Abelian 3-form field by means of a
topological mass term. An extended covariant derivative is introduced to
minimally couple a Dirac field to the potential, while this same
covariant derivative non-minimally couples the 3-form field to the charged
fermion. A number of properties are discussed in 5D; in particular, the
appearance of a topological fermionic current. A 4-dimensional reduced version
of the model is investigated and, { \bf in addition to the electric- and
magnetic-sort of fields,} there emerges an extra set of electric- and
magnetic-like fields which contribute a negative pressure and may be identified
as a possible fraction of dark energy. The role of the topological fermionic
current is also contemplated upon dimensional reduction from 5D to 4D. Other
issues we present in 4 space-time dimensions are the emergence {\bf of a
pseudo-scalar massive particle,} an extra massive neutral gauge boson,{\bf
which we interpret as a kind of paraphoton}, and the calculation of spin- and
velocity-dependent interparticle potentials associated to the exchange of the
intermediate bosonic fields of the model.Comment: -- 30 pages -- L. P. R. Ospedal appears as a new co-author;
modifications by inclusion of the gravitational sector and the attainment of
a spin- and velocity-dependent potential as an application have been worked
out in this Revised Versio
Hamiltonian symplectic embedding of the massive noncommutative U(1) Theory
We show that the massive noncommutative U(1) theory is embedded in a gauge
theory using an alternative systematic way, which is based on the symplectic
framework. The embedded Hamiltonian density is obtained after a finite number
of steps in the iterative symplectic process, oppositely to the result proposed
using the BFFT formalism. This alternative formalism of embedding shows how to
get a set of dynamically equivalent embedded Hamiltonian densities.Comment: 16 pages, no figures, revtex4, corrected version, references
additione
Considerations on the ModMax electrodynamics in the presence of an electric and magnetic background
The properties of the modified Maxwell electrodynamics (ModMax) are
investigated in the presence of an external and uniform electromagnetic field.
We expand the non-linear theory around an electromagnetic background up to
second order in the propagating fields to obtain the permittivity and
permeability tensors, the dispersion relations, the group velocity and the
refractive index of the wave as functions of the uniform electric and magnetic
fields. The case in which these background fields are perpendicular is
analyzed. The birefringence phenomenon is discussed where the parameter of the
non-linear theory has a fundamental role. We calculate the difference of the
refractive indices as function of the ModMax parameter, and of the electric and
magnetic fields. Finally, we compute the interaction energy for an axionic
ModMax electrodynamics in the presence of an external magnetic background
fields, within the framework of the gauge-invariant, but path-dependent
variables formalism. Our results show that the interaction energy contains a
linear term leading to the confinement of static probe charges.Comment: 10 pages, 2 figure
Considerations on anomalous photon and Z-boson self-couplings from the Born-Infeld weak hypercharge action
We investigate the effects of the Born-Infeld action on the Abelian sector of
the electroweak model. The consequence of this approach is the emergence of
anomalous couplings in the neutral sector of the -gauge boson and photon.
These new couplings consist of quartic interactions of the photon with the
-particle, as for example, three-photon-and-one- vertex. With that, we
obtain the decay width of from which we impose a bound on the
Born-Infeld parameter. Other bounds are also obtained from the photon quartic
couplings. Subsequently, we consider the presence of an external uniform
magnetic field in connection with this Born-Infeld weak hypercharge model. The
magnetic background field yields new kinematic effects, like the kinetic mixing
between the photon and the -boson, and we obtain thereby the corresponding
dispersion relations for the mixed photon--particle system. Finally, we
calculate the lowest-order modifications to the interaction energy for the
anomalous coupling , within the framework of the gauge-invariant but
path-dependent variables formalism. Our results show that the interaction
energy contains a linear term leading to the confinement of static probe
charges. With the help of the potential that comes out, interparticle forces
are estimated.Comment: 11 pages, no figures, version published in the EPJ
A Dirac-material-inspired non-linear electrodynamic model
We propose and study the properties of a non-linear electrodynamics that
emerges inspired on the physics of Dirac materials. This new electrodynamic
model is an extension of the one-loop corrected non-linear effective Lagrangian
computed in the work of ref. [3]. In the particular regime of a strong magnetic
and a weak electric field, it reduces to the photonic non-linear model worked
out by the authors of ref. [3]. We pursue our investigation of the proposed
model by analyzing properties of the permittivity and permeability tensors, the
energy-momentum tensor and wave propagation effects in presence of a uniform
magnetic background. It is shown that the electrodynamics here presented
exhibits the vacuum birefringence phenomenon. Subsequently, we calculate the
lowest-order modifications to the interaction energy, considering still the
presence of a uniform external magnetic field. Our analysis is carried out
within the framework of the gauge-invariant but path-dependent variables
formalism. The calculation reveals a screened Coulomb-like potential with an
effective electric charge that runs with the external magnetic field but, as
expected for Dirac-type materials, the screening disappears whenever the
external magnetic field is switched off.Comment: 9 pages, 3 figure
The axion-photon mixing in non-linear electrodynamic scenarios
In this contribution, we re-assess some aspects of axionic electrodynamics by
coupling non-linear electromagnetic effects to axion physics. We present a
number of motivations to justify the coupling of the axion to the photon in
terms of a general non-linear extension of the electromagnetic sector. Our
emphasis in the paper relies on the investigation of the constitutive
permittivity and permeability tensors, for which the axion contributes by
introducing dependence on the frequency and wave vector of the propagating
radiation. Also, we point out how the axion mass and the axion-photon-photon
coupling constant contribute to a dispersive behavior of the electromagnetic
waves, in contrast to what happens in the case of non-linear extensions, when
effective refractive indices appear which depend only on the direction of the
propagation with respect to the external fields. The axion changes this picture
by yielding refractive indices with dependence on the wavelength. We apply our
results to the special case of the Born-Infeld Electrodynamics and we show that
it becomes birefringent whenever the axion is coupled. The paper is
supplemented by an Appendix, where we approach the recent discussion on the
controversy in defining the Poynting vector of axionic electrodynamics. We
present our path to tackle the question and give the expressions we work out
for both the Poynting vector and the momentum density transported by the waves.Comment: 30 pages, no figure
Probing the interference between non-linear, axionic and space-time-anisotropy effects in the QED vacuum
We pursue the investigation of a generic non-linear extension of axionic
electrodynamics (ED) in a Carroll-Field-Jackiw (CFJ) scenario that implements
Lorentz-symmetry violation (LSV). The model consists of an arbitrary non-linear
ED action coupled to the axion field in presence of an anisotropy four-vector
that realizes the breaking of Lorentz symmetry under the particle point of
view. The non-linear electromagnetic field is expanded around a constant and
uniform magnetic background up to second order in the propagating photon field.
Our attention is the study of the material properties of the vacuum in the
particular case of a space-like CFJ -vector. The dispersion relations
associated to the plane wave solutions are explicitly worked out in two
situations: the magnetic background perpendicular and parallel to the wave
direction. We extend these results to consider the analysis of the
birefringence phenomenon in presence of non-linearity, the axion and the LSV
manifested through the spatial anisotropy. Three specific proposals of
non-linear ED are contemplated: Euler-Heisenberg, Born-Infeld and the Modified
Maxwell ED. Throughout the paper, we shall justify why we follow the unusual
path of connecting, in a single Lagrangian density, three pieces of physics
beyond the Standard Model, namely, non-linearity, axions and LSV. We anticipate
that we shall not be claiming that the simultaneous introduction of these three
topics beyond the Standard Model will bring new insights or clues for the
efforts to detect axions or to constrain parameters associate to both
non-linear ED and LSV physics . Our true goal is to actually inspect and
describe how axionic, non-linear and LSV effects interfere with one another
whenever physical entities like refraction indices and birefringence are
computed in presence of an external constant and homogeneous magnetic
background.Comment: 27 pages, no figure
Operatorial quantization of Born-Infeld Skyrmion model and hidden symmetries
The SU(2) collective coordinates expansion of the Born-Infeld\break Skyrmion
Lagrangian is performed. The classical Hamiltonian is computed from this
special Lagrangian in approximative way: it is derived from the expansion of
this non-polynomial Lagrangian up to second-order variable in the collective
coordinates. This second-class constrained model is quantized by Dirac
Hamiltonian method and symplectic formalism. Although it is not expected to
find symmetries on second-class systems, a hidden symmetry is disclosed by
formulating the Born-Infeld Skyrmion %model as a gauge theory. To this end we
developed a new constraint conversion technique based on the symplectic
formalism. Finally, a discussion on the role played by the hidden symmetry on
the computation of the energy spectrum is presented.Comment: A new version of hep-th/9901133. To appear in JP
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