Born-Infeld Electrodynamics and Euler-Heisenberg-like Model: outstanding examples of the lack of commutativity among quantized truncated actions and truncated quantized actions

We calculate the lowest-order corrections to the static potential for both the generalized Born-Infeld Electrodynamics and an Euler-Heisenberg-like model, in the presence of a constant external magnetic field. Our analysis is carried out within the framework of the gauge-invariant but path-dependent variables formalism. The calculation reveals a long-range correction ( {\raise0.7ex\hbox{1} \mathord{\left/ {\vphantom {1 {r^5}}}\right.\kern-\nulldelimiterspace} \lower0.7ex\hbox{{r^5}}}-type) to the Coulomb potential for the generalized Born-Infeld Electrodynamics. Interestingly enough, in the Euler-Heisenberg-like model, the static potential remains Coulombian. Therefore, contrary to popular belief, the quantized truncated action and the truncated quantized action do not commute at all.Comment: 7 pages. Title changed, revised version. To appear in Int. J. Mod. Phys.

On scale symmetry breaking and confinement in D=3 models

Within the framework of the gauge-invariant, but path-dependent, variables formalism, we study the connection between scale symmetry breaking and confinement in three-dimensional gluodynamics. We explicitly show that the static potential profile contains a linear potential, leading to the confinement of static charges. Also, we establish a new type of equivalence among different three-dimensional effective theories.Comment: 6 pages, references adde

On condensation of charged scalars in D=3 dimensions

By using the gauge-invariant, but path-dependent, variables formalism, we study the impact of condensates on physical observables for a three-dimensional Higgs-like model. As a result, for the case of a physical mass term like $m_H^2 \phi ^ * \phi$, we recover a screening potential. Interestingly enough, in the case of a "wrong-sign" mass term $- m_H^2 \phi ^ * \phi$, unexpected features are found. It is shown that the interaction energy is the sum of an effective-Bessel and a linear potential, leading to the confinement of static charges. However, when a Chern-Simons term is included, the surprising result is that the theory describes an exactly screening phase.Comment: 13 page

Aspects of Magnetic Field Configurations in Planar Nonlinear Electrodynamics

In the framework of three-dimensional Born-Infeld Electrodynamics, we pursue an investigation of the consequences of the space-time dimensionality on the existence of magnetostatic fields generated by electric charges at rest in an inertial frame, which are present in its four-dimensional version. Our analysis reveals interesting features of the model. In fact, a magnetostatic field associated with an electric charge at rest does not appear in this case. Interestingly, the addition of the topological term (Chern-Simons) to Born-Infeld Electrodynamics yields the appearance of the magnetostatic field. We also contemplate the fields associated to the would-be-magnetic monopole in three dimensions.Comment: 8 page