arXiv subjects

José A. Helayel-Neto

Publications and source records attributed to José A. Helayel-Neto.

3 recordsLinked to original sources

arXiv2016

Troubles with the radiation reaction in electrodynamics

The dynamics of a radiating charge is one of the oldest unsettled problems in classical physics. The standard Lorentz-Abraham-Dirac (LAD) equation of motion is known to suffer from several pathologies and ambiguities. This paper briefly reviews these issues, and reports on a new model that fixes these difficulties in a natural way. This model is based on a hypothesis that there is an infinitesimal time delay between action and reaction. This can be related to Feynman's regularization scheme, leading to a quasi-local QED with a natural UV cutoff, hence without the need for renormalization as the divergences are absent. Besides leading to a pathology-free equation of motion, the new model predicts a modification of the Larmor formula that is testable with current and near future ultra-intense lasers.

hep-th↗

arXiv2010

Un-graviton corrections to the Schwarzschild black hole

We introduce an effective action smoothly extending the standard Einstein-Hilbert action to include un-gravity effects. The improved field equations are solved for the un-graviton corrected Schwarzschild geometry reproducing the Mureika result. This is an important test to confirm the original ``guess'' of the form of the Un-Schwarzschild metric. Instead of working in the weak field approximation and ``dressing'' the Newtonian potential with un-gravitons, we solve the ``effective Einstein equations'' including all order un-gravity effects. An unexpected ``bonus'' of accounting un-gravity effects is the fractalisation of the event horizon. In the un-gravity dominated regime the event horizon thermodynamically behaves as fractal surface of dimensionality twice the scale dimension d_U.

hep-ph↗

arXiv2010

Some aspects of a Chern-Simons-like coupling in an external magnetic field

For a gauge theory which includes a light massive vector field interacting with the familiar photon U(1)_{QED} via a Chern-Simons- like coupling, we study the static quantum potential. Our analysis is based on the gauge-invariant, but path-dependent, variables formalism. The result is that the theory describes an exactly screening phase. Interestingly enough, this result displays a marked departure of a qualitative nature from the axionic elctrodynamics result. However, the present result is analogous to that encountered in the coupling between the familiar photon U(1)_{QED} and a second massive gauge field living in the so-called hidden-sector U(1)_h, inside a superconducting box.

hep-th↗