arXiv subjects
Publications and source records attributed to J. A. Helayël-Neto.
We introduce and discuss the method of Linear Delta Expansion for the calculation of effective potentials in superspace, by adopting the improved version of the super-Feynman rules. Calculations are carried out up to two-loops and an expression for the optimized Kähler potential is worked out.
We study magnetic monopoles in a Lorentz- and CPT-odd electrodynamical framework in (3+1) dimensions. This is the standard Maxwell model extended by means of a Chern-Simons-like term, $b_μ\tilde{F}^{μν}A_ν$ ($b_μ$ constant), which respects gauge invariance but violates both Lorentz and CPT symmetries (as a consequence, duality is also lost). Our main interest concerns the analysis of the model in the presence of Dirac monopoles, so that the Bianchi identity no longer holds, which naively yields the non-conservation of electric charge. Since gauge symmetry is respected, the issue of charge conservation is more involved. Actually, the inconsistency may be circumvented, if we assume that the appearance of a monopole induces an extra electric current. The reduction of the model to (2+1) dimensions in the presence of both the magnetic sources and Lorentz-violating terms is presented. There, a quantization condition involving the scalar remnant of $b_μ$, say, the mass parameter, is obtained. We also point out that the breaking of duality may be associated with an asymmetry between electric and magnetic sources in this background, so that the electromagnetic force experienced by a magnetic pole is supplemented by an extra term proportional to $b_μ$, whenever compared to the one acting on an electric charge.
Modifications of the electromagnetic Maxwell Lagrangian in four dimensions have been considered by some authors. One may include an explicit massive term (Proca) and a topological but not Lorentz-invariant term within certain observational limits. We find the dual-corresponding gauge invariant version of this theory by using the recently suggested gauge embedding method. We enforce this dualisation procedure by showing that, in many cases, this is actually a constructive method to find a sort of parent action, which manifestly establishes duality. We also use the gauge invariant version of this theory to formulate a Batalin-Vilkovisky quantization and present a detailed discussion on the excitation spectrum.
We take as starting point the planar model arising from the dimensional reduction of the Maxwell Electrodynamics with the (Lorentz-violating) Carroll-Field-Jackiw term. We then write and study the extended Maxwell equations and the corresponding wave equations for the potentials. The solution to these equations show some interesting deviations from the usual MCS Electrodynamics, with background-dependent correction terms. In the case of a time-like background, the correction terms dominate over the MCS sector in the region far from the origin, and establish the behaviour of a massless Electrodynamics (in the electric sector). In the space-like case, the solutions indicate the clear manifestation of spatial anisotropy, which is consistent with the existence of a privileged direction is space.
A generic massive Thirring Model in three space-time dimensions exhibits a correspondence with a topologically massive bosonized gauge action associated to a self-duality constraint, and we write down a general expression for this relationship. We also generalize this structure to $d$ dimensions, by adopting the so-called doublet approach, recently introduced. In particular, a non- conventional formulation of the bosonization technique in higher dimensions (in the spirit of $d=3$), is proposed and, as an application, we show how fermionic (Thirring-like) representations for bosonic topologically massive models in four dimensions may be built up.
Classical Maxwell and Maxwell-Chern-Simons (MCS) Electrodynamics in (2+1)D are studied in some details. General expressions for the potential and fields are obtained for both models, and some particular cases are explicitly solved. Conceptual and technical difficulties arise, however, for accelerated charges. The propagation of electromagnetic signals is also studied and their reverberation is worked out and discussed. Furthermore, we show that a Dirac-like monopole yields a (static) tangential electric field. We also discuss some classical and quantum consequences of the field created by such a monopole when acting upon an usual electric charge. In particular, we show that at large distances, the dynamics of one single charged particle under the action of such a potential and a constant (external) magnetic field as well, reduces to that of one central harmonic oscillator, presenting, however, an interesting angular sector which admits energy-eigenvalues. Among other peculiarities, both sectors, the radial and the angular one, present non-vanishing energy-eigenvalues for their lowest level. Moreover, those associated to the angle are shown to respond to discrete shifts of such a variable. We also raise the question whether the formation of bound states is possible in the system.
The supersymmetric generalization of a recently proposed Abelian axial gauge model with antisymmetric tensor matter fields is presented.
In this paper, we present a parity-preserving QED3 with spontaneous breaking of a local U(1)-symmetry. The breaking is accomplished by a potential of the \vf^6-type. It is shown that a net attractive interaction appears in the Møller scattering (s and p-wave scattering between two electrons) as mediated by the gauge field and a Higgs scalar. This might favour a pair-condensation mechanism.
In this letter the algebraic renormalization method, which is independent of any kind of regularization scheme, is presented for the parity-preserving QED_3 coupled to scalar matter in the symmetric regime, where the scalar assumes vanishing vacuum expectation value, $<ϕ>=0$. The model shows to be stable under radiative corrections and anomaly free.
In this letter the algebraic renormalization method, which is independent of any kind of regularization scheme, is presented for the parity-preserving QED_3 coupled to scalar matter in the broken regime, where the scalar assumes a finite vacuum expectation value, $<\vf> = v$. The model shows to be stable under radiative corrections and anomaly free.
We present a supersymmetric non-linear $\s$-model built up in the $N=1$ superspace of Atiyah-Ward space-time. A manifold of the Kähler type comes out that is restricted by a particular decomposition of the Kähler potential. The gauging of the $\s$-model isometries is also accomplished in superspace.