271 research outputs found
A note on nonlinear electrodynamics
We explore the physical consequences of a new nonlinear electrodynamics, for
which the electric field of a point-like charge is finite at the origin, as in
the well-known Born-Infeld electrodynamics. However, contrary to the latter, in
this new electrodynamics the phenomenon of birefringence and dichroism take
place in the presence of external magnetic fields. Subsequently we study the
interaction energy, within the framework of the gauge-invariant but
path-dependent variables formalism. Interestingly enough, the static potential
profile contains a linear potential leading to the confinement of static
charges.Comment: 5 pages. arXiv admin note: substantial text overlap with
arXiv:1607.0299
D topological superconductors: screening and confinement in presence of external fields
Adopting the gauge-invariant and path-dependent variables formalism, we
compute the interaction energy for a topological field theory describing
D topological superconductors in presence of external fields. As a
result, in the case of a constant electric field- strength expectation value,
we show that the interaction energy describes a purely screening phase, encoded
in a Yukawa potential. On the other hand, in the case of a constant magnetic
field-strength and for a very small Josephson coupling constant, the
particle-antiparticle binding potential displays a linear term leading to the
confinement of static charge probes along with a screening contribution.Comment: 6 page
Remarks on the static potential in theories with Lorentz violation terms
We study the impact of Lorentz violating terms on a physical observable for
both electrodynamics of chiral matter and an Abelian Higgs-like model in
dimensions. Our calculation is done within the framework of the
gauge-invariant, but path-dependent, variables formalism. Interestingly enough,
for electrodynamics of chiral matter we obtain a logarithmic correction to the
usual static Coulomb potential. Whereas for a Abelian Higgs model with a
Lorentz-breaking term, our result displays new corrections to the Yukawa
potential.Comment: 7 page
On the Zitterbewegung Transient Regime in a Coarse-Grained Space-Time
In the present contribution, by studying a fractional version of Dirac's
equation for the electron, we show that the phenomenon of Zitterbewegung in a
coarse-grained medium exhibits a transient oscillatory behavior, rather than a
purely oscillatory regime, as it occurs in the integer case, . Our
result suggests that, in such systems, the Zitterbewegung-type term related to
a trembling motion of a quasiparticle is tamed by its complex interactions with
other particles and the medium. This can justify the difficulties in the
observation of this interesting phenomenon. The possibility that the
Zitterbewegung be accompanied by a damping factor supports the viewpoint of
particle substructures in Quantum Mechanics.Comment: 11 pages, 1 figure. This paper has been published in J. Adv. Phys. 7
(2015) 144
Remarks on nonlinear Electrodynamics
We consider both generalized Born-Infeld and Exponential Electrodynamics. The
field-energy of a point-like charge is finite only for Born-Infeld-like
Electrodynamics. However, both Born-Infeld-type and Exponential Electrodynamics
display the vacuum birefringence phenomenon. Subsequently, we calculate the
lowest-order modifications to the interaction energy for both classes of
Electrodynamics, within the framework of the gauge-invariant path-dependent
variables formalism. These are shown to result in long-range (- type)
corrections to the Coulomb potential. Once again, for their non-commutative
versions, the interaction energy is ultraviolet finite.Comment: 10 pages. arXiv admin note: substantial text overlap with
arXiv:1312.515
Anomalous g-Factors for Charged Leptons in a Fractional Coarse-Grained Approach
In this work, we investigate aspects of the electron, muon and tau
gyromagnetic ratios (g-factor) in a fractional coarse-grained scenario, by
adopting a Modified Riemann-Liouville (MRL) fractional calculus. We point out
the possibility of mapping the experimental values of the specie's g-factors
into a theoretical parameter which accounts for fractionality, without
computing higher-order QED calculations. We wish to understand whether the
value of (g-2) may be traced back to a fractionality of space-time.The
justification for the difference between the experimental and the theoretical
value g=2 stemming from the Dirac equation is given in the terms of the
complexity of the interactions of the charged leptons, considered as
pseudo-particles and "dressed" by the interactions and the medium. Stepwise, we
build up a fractional Dirac equation from the fractional Weyl equation that, on
the other hand, was formulated exclusively in terms of the helicity operator.
From the fractional angular momentum algebra, in a coarse-grained scenario, we
work out the eigenvalues of the spin operator. Based on the standard
electromagnetic current, as an analogy case, we write down a fractional
Lagrangian density, with the electromagnetic field minimally coupled to the
particular charged lepton. We then study a fractional gauge-like invariance
symmetry, formulate the covariant fractional derivative and propose the spinor
field transformation. Finally, by taking the non-relativistic regime of the
fractional Dirac equation, the fractional Pauli equation is obtained and, from
that, an explicit expression for the fractional g-factor comes out that is
compared with the experimental CODATA value. Our claim is that the different
lepton species must probe space-time by experiencing different fractionalities,
once the latter may be associated to the effective interactions of the
different families with the medium.Comment: 15 page
Remarks on a model with topological mass from gauging spin
Aspects of screening and confinement are reassessed for a model
with topological mass with the gauging of spin. Our discussion is carried out
using the gauge-invariant, but path-dependent, variables formalism. We
explicitly show that the static potential profile is the sum of a Yukawa and a
linear potential, leading to the confinement of static external charges.
Interestingly enough, similar results are obtained in a theory of antisymmetric
tensor fields that results from the condensation of topological defects as a
consequence of the Julia-Toulouse mechanism.Comment: 5 page
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