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J. A. Helayel-Neto

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

At least 55 records · Page 3Linked to original sources
arXiv2003

Remarks on Charged Vortices in the Maxwell-Chern-Simons Model

We study vortex-like configuration in Maxwell-Chern-Simons Electrodynamics. Attention is paid to the similarity it shares with the Nielsen-Olesen solutions at large distances. A magnetic symmetry between a point-like and an azimuthal-like current in this framework is also pointed out. Furthermore, we address the issue of a neutral and spinless particle interacting with a charged vortex, and obtain that the Aharonov-Casher-type phase depends upon mass and distance parameters.

hep-th↗
arXiv2003

Remarks on the Causality, Unitarity and Supersymmetric Extension of the Lorentz and CPT-Violating Maxwell-Chern-Simons Model

The gauge-invariant Chern-Simons-type Lorentz- and CPT-breaking term is here re-assessed and issues like causality, unitarity, spontaneous gauge-symmetry breaking are investigated. Moreover, we obtain a minimal extension of such a system to a supersymmetric environment. We comment on resulting peculiar self-couplings for the gauge sector, as well as on background contribution for gaugino masses.

hep-th↗
arXiv2003

Supersymmetric Extension of the Lorentz and CPT-Violating Maxwell-Chern-Simons Model

Focusing on gauge degrees of freedom specified by a 1+3 dimensions model hosting a Maxwell term plus a Lorentz and CPT non-invariant Chern-Simons-like contribution, we obtain a minimal extension of such a system to a supersymmetric environment. We comment on resulting peculiar self-couplings for the gauge sector, as well as on background contribution for gaugino masses. Furthermore, a non-polynomial generalization is presented.

hep-th↗
arXiv2003

On the relation between the propagators of dual theories

In this paper, we show that the propagator of the dual of a general Proca-like theory, derived from the gauging iterative Noether Dualization Method, can be written by means of a simple relation between known propagators. This result is also a demonstration that the Lagrangian obtained by dualization describes the same physical particles as the ones present in the original theory at the expense of introducing new non-physical (ghosts) excitations.

hep-th↗
arXiv2003

Dimensional Reduction of a Lorentz and CPT-violating Maxwell-Chern-Simons Model

Taking as starting point a Lorentz and CPT non-invariant Chern-Simons-like model defined in 1+3 dimensions, we proceed realizing its dimensional reduction to D=1+2. One then obtains a new planar model, composed by the Maxwell-Chern-Simons (MCS) sector, a Klein-Gordon massless scalar field, and a coupling term that mixes the gauge field to the external vector, $v^μ$. In spite of breaking Lorentz invariance in the particle frame, this model may preserve the CPT symmetry for a single particular choice of $v^μ$. Analyzing the dispersion relations, one verifies that the reduced model exhibits stability, but the causality can be jeopardized by some modes. The unitarity of the gauge sector is assured without any restriction, while the scalar sector is unitary only in the space-like case. PACS numbers: 11.10.Kk; 11.30.Cp; 11.30.Er; 12.60.-i

hep-th↗
arXiv2002

Electron-electron Bound States in Parity-Preserving QED3

By considering the Higgs mechanism in the framework of a parity-preserving Planar Quantum Electrodynamics, one shows that an attractive electron-electron interaction may come out. The e-e interaction potential emerges as the non-relativistic limit of the Moller scattering amplitude and it may result attractive with a suitable choice of parameters. Numerical values of the e-e binding energy are obtained by solving the two-dimensional Schrodinger equation. The existence of bound states is to be viewed as an indicative that this model may be adopted to address the pairing mechanism in some systems endowed with parity-preservation.

hep-th↗
arXiv2002

Propagating Torsion in 3D-Gravity and Dynamical Mass Generation

In this paper, fermions are minimally coupled to 3D-gravity where a dynamical torsion is introduced. A Kalb-Ramond field is non-minimally coupled to these fermions in a gauge-invariant way. We show that a 1-loop mass generation mechanism takes place for both the 2-form gauge field and the torsion. As for the fermions, no mass is dynamically generated: at 1-loop, there is only a mass shift proportional to the Yukawa coupling whenever the fermions have a non-vanishing tree-level mass.

hep-th↗
arXiv2002

N=2-Supersymmetric Dynamics of a Spin-1/2 Particle in an Extended External Field

One considers the quantum dynamics of a charged spin-1/2 particle in an extended external eletromagnetic field that arises from the reduction of a 5-dimensional Abelian gauge theory. The non-relativistic regime of the reduced 4D-dynamics is worked out and one identifies the system as a sector of an N=2-supersymmetric quantum-mechanical dynamics. The full supersymmetric model is studied and one checks the algebra of the fermionic charges; the conclusion is that no central charge drops out. The possible rôle of the extra external fields, a scalar and a magnetic-like field, is discussed.

hep-th↗
arXiv2002

Cosmic String in the Supersymmetric CSKR Theory

We study a cosmic string solution of an N=1-supersymmetric version of the Cremmer-Scherk-Kalb-Ramond (CSKR) Lagrangian coupled to a vector superfield by means of a topological mass term. The 2-form gauge potential is proposed to couple non-minimally to matter, here described by a chiral scalar superfield. The important outcome is that supersymmetry is kept exact both in the core and in the exterior region of the string. We contemplate the bosonic configurations and it can be checked that the solutions saturate the Bogomolnyi bound. A glimpse on the fermionic zero modes is also given.

hep-th↗
arXiv2002

Dirac-like Monopoles in Three Dimensions and Their Possible Influences on the Dynamics of Particles

Dirac-like monopoles are studied in three-dimensional Abelian Maxwell and Maxwell-Chern-Simons models. Their scalar nature is highlighted and discussed through a dimensional reduction of four-dimensional electrodynamics with electric and magnetic sources. Some general properties and similarities of them when are considered in Minkowski or Euclidian space are mentioned. However, by virtue of the structure of the space-time in which they are considered a number of differences among them take place. Furthermore, we pay attention to some consequences of these objects when acting upon usual particles. Among other subjects, special attention is given to the study of a Lorentz-violating non-minimal coupling between neutral fermions and the field generated by a monopole alone. In addition, an analogue of the Aharonov-Casher effect is discussed in this framework.

hep-th↗
arXiv2001

Generalized Gauge Transformations and Regularized $λϕ^{4}$-type Abelian Vertices

Abelian Lagrangians containing $λϕ^{4}$-type vertices are regularized by means of a suitable point-splitting scheme combined with generalized gauge transformations. The calculation is developped in details for a general Lagrangian whose fields (gauge and matter ones) satisfy usual conditions. We illustrate our results by considering some special cases, such as the $(\barψψ)^{2}$ and the Avdeev-Chizhov models. Possible application of our results to the Abelian Higgs model, whenever spontaneous symmetry breaking is considered, is also discussed. We also pay attention to a number of features of the point-split action such as the regularity and non-locality of its new ``interacting terms''.

hep-th↗
arXiv2001

Huyghens Principle, Planck Law: Peculiarities in the Behavior of Planar Photons

Huyghens principle and Planck law are studied in Maxwell and Maxwell-Chern-Simons frameworks in (2+1) dimensions. Contrary to (3+1) dimensions, massless photons are shown to violate Huyghens principle in planar world. In addition, we obtain that Planck law is no longer proportional to $ν^3$, but to the squared frequency, $ν^2$, of the planar photons. We also briefly discuss possible physical consequences of these results.

hep-th↗
arXiv2001

Coupling Nonlinear Sigma-Models to Relaxed Yang- Mills Supermultiplets in (2,0)-Superspace

Following a previous work on Abelian (2,0)-gauge theories, one reassesses here the task of coupling (2,0) relaxed Yang-Mills superpotentials to a (2,0)- nonlinear $σ$-model, by gauging the isotropy or the isometry group of the latter. One pays special attention to the extra ``chiral-like'' component-field gauge potential that comes out from the relaxation of superspace constraints.

hep-th↗
arXiv2001

Electron-electron bound states in parity-preserving QED_3 applied to high-T_c cuprate superconductors

We consider a parity-preserving QED_3 model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron-electron interaction potential underlying high-T_c superconductivity. The fact that the resulting potential, -C_s K_{0}(Mr), is non-confining and ``weak'' (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameter, is then applied to the Schrödinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasi-planar cuprate superconductors. The data analyzed here suggest an energy scale of 1-10 meV for the breaking of the U(1)-symmetry.

cond-mat.supr-con↗
arXiv2001

Generalized Gauge Transformations and Regularized $λϕ^4$-type Abelian Vertices

Abelian Lagrangians containing Phi^4-type vertices are regularized by means of a suitable point-splitting scheme combined with generalized gauge transformations.. The calculation is developed in details for a general Lagrangean, whose fields (gauge and matter ones) satisfy usual conditions. We illustrate our results by considering some special cases, such as the ($\overlineψψ)^2 and a modified version of the Avddev-Chizhov models. Possible application of our results to the Abelian Higgs model, whenever spontaneous symmetry breaking is considered, is also discussed. We also pay attention to a number of features of the point-split action such as the regularity and non-locality of its new ``interacting terms''.

hep-th↗
arXiv2001

Electron-electron attractive interaction in Maxwell-Chern-Simons QED3 at zero temperature

One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED3 with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model.

hep-th↗