arXiv subjects

A. A. Nogueira

Publications and source records attributed to A. A. Nogueira.

15 recordsLinked to original sources

arXiv2026

External Sources in Pseudo-Quantum Electrodynamics

In this letter, we investigate the interaction between stationary point-like external sources within the framework of Pseudo-Quantum Electrodynamics (PQED). Besides ordinary electric charges, we consider configurations involving Dirac points and generalized topological sources. For the configurations analyzed, we compute the corresponding interaction energies, forces, torques, and electromagnetic field configurations. Furthermore, we compare the results obtained in PQED with those arising in ordinary planar Maxwell electrodynamics, showing that the nonlocal character of PQED gives rise to physical effects with no counterpart in the conventional local planar theory. In particular, our results show that topological sources induce intrinsically anisotropic and non-central interactions, leading to the emergence of nontrivial torques between the interacting objects. The directional character of these interactions suggests possible applications in the effective description of topological defects and anisotropic phenomena in planar condensed matter systems.

hep-th↗

arXiv2026

Topological insulator realization induced by fermionic interaction through BF mediators

This paper demonstrates that ordinary fermions, interacting via a BF mediator, form a renormalized structure with non-trivial topological properties. We explore the analogy between the renormalized fermion and a subset of real three-dimensional topological insulators (TIs) in the vicinity of their single Dirac cones. Using the typical magnitude of TI lattice and gaps, we constrain model parameters. The topological structure induced by radiative corrections enters a class of modified Dirac equations, ensuring the existence of helical gapless near-boundary modes. We derive an effective potential for inter-quasi-particle interactions that incorporates finite-size effects in the axial direction, revealing signatures of spin-orbit coupling and time-reversal invariance. Remarkably, particles with different spins do not interact via the characteristic spin-orbit coupling, and a non-central spin-dependent force arises. We also address the behavior of the system in the phase transition associated with the thin-film limit.

cond-mat.mes-hall↗

arXiv2026

Point-Like Charges and Dirichlet Boundary Conditions in a Nonlocal Scalar Field Theory

In this paper, we investigate novel classical non-local effects in scalar field theory arising from the presence of external sources and a material boundary. Specifically, we consider a model in which the standard Klein-Gordon field theory is modified by a non-local term. First, we analyze the interaction between stationary field sources modeled as point-like scalar charges. In specific configurations, the resulting interparticle potential reduces to the Cornell form. Then, we examine the model in the presence of a Dirichlet plane, computing both the scalar field propagator and the interaction force between the Dirichlet plane and a point-like scalar charge. Additionally, we demonstrate the failure of the image method in this non-local context and compare our results with those obtained in non-local electrodynamics and in the standard Klein-Gordon field theory.

hep-th↗

arXiv2024

Covariant operator formalism for higher derivative systems: Vector spin-$0$ dual model as a prelude to generalized QED$_4$

In this work we extend the Kugo-Ojima-Nakanishi covariant operator formalism to quantize two higher derivative systems, considering their extended phase space structures. More specifically, the one describing spin-$0$ particles by a vector field and the generalized electrodynamics. We investigate the commutator structure of these theories and present the definition of their physical Hilbert subspaces. The first model presents a reducible gauge symmetry, implying the necessity of two sets of auxiliary fields. The massless limit is also carefully analyzed. After this prelude, the generalized QED$_4$ can be investigated with such machinery. Regarding the interacting regime, the positive norm subspace is no longer time invariant, since the interaction can create negative norm states from an initially ghost-free one. Then, we furnish an alternative description of the situation by analyzing a set of spectral representations highlighting the lack of positivity associated with the well-known ultraviolet improvement. Finally, based on these efforts and also on recent discussions about Lee-Wick like models, we prove that it is possible to establish a specific higher derivative interacting model compatible with establishing a time-invariant positive norm subspace.

hep-th↗

arXiv2023

Path Integral Quantization of Generalized Stueckelberg Electrodynamics: A Faddeev-Jackiw Approach

We build a setup for path integral quantization through the Faddeev-Jackiw approach, extending it to include Grassmannian degrees of freedom, to be later implemented in a model of generalized electrodynamics that involves fourth-order derivatives in the components of a massive vector field being endowed with gauge freedom, due to an additional scalar field. Namely, the generalized Stueckelberg electrodynamics. In the first instance, we work on the free case to gain some familiarity with the program and, subsequently, we add the interaction with fermionic matter fields to complete our aim. In addition to deriving the correct classical brackets for such a model, we get the full expression for the associated generating functional and its associated integration measure.

hep-th↗

arXiv2023

Fermionic dark matter-photon quantum interaction: A mechanism for darkness

Mass dimension one fermionic fields are prime candidates to describe dark matter, due to their intrinsic neutral nature, as they are constructed as eigenstates of the charge conjugation operator with dual helicity. To formulate the meaning of the darkness, the fermion-photon coupling is scrutinized with a Pauli-like interaction, and the path integral is then formulated from the phase space constraint structure. Ward-Takahashi-like identities and Schwinger-Dyson equations, together with renormalizability, are employed to investigate a phenomenological mechanism to avoid external light signals. Accordingly, the non-polarized pair annihilation and Compton-like processes are shown to vanish at the limit of small scattering angles even if considering 1-loop radiative corrections, reinforcing the dark matter interpretation. However, dark matter interactions with nucleons are still possible. Motivated by recent nucleon-recoil experiments to detect dark matter, we furnish a consistent theoretical setup to describe interaction with the photon compatible with the prevalence of darkness.

hep-ph↗

arXiv2022

A Generalized Stueckelberg-Higgs gauge theories

The aim of this work is to discuss and explore some generalized aspects of generation of photon mass respecting gauge symmetry. We introduce generalized Stueckelberg and Higgs gauge theories and present the classical and quantum frameworks related to them. We construct the quantum theory by writing the transition amplitude in the Fadeev-Senjanovic formalism and put it in a covariant form by the Fadeev-Popov method. We also analyze the independence of the transition amplitude by gauge parameters via BRS-T symmetry. Even in the generalized context, the Stueckelberg structure influences the quantization process of the Higgs theory in the 't Hooft's fashion, in which an intimate relationship between the Stueckelberg compensating field and the Goldstone boson arises.

hep-th↗

arXiv2022

Spontaneous symmetry breakings in the singlet scalar Yukawa model within the auxiliary field method

The aim of this work is to investigate the occurrence of two different spontaneous symmetry breakings {at} two levels of the description of fermion-scalar field model, by means of a set of gap equations and {with} a background field effective action. For that, we consider the Yukawa model, as a toy model for interactions between non-massive fermions intermediated by a self-interacting real scalar field. This model has at stakes two symmetries at the classical level that, as we know, might be spontaneously or dynamically broken with mass generation for the particles. The auxiliary field method is considered and it produces coupled renormalized gap equations. The effective action is then written with quantum contributions by {the} external background {field} method. We brought to light how the renormalization procedure affects the physical gaps, investigate its properties, and discuss the connection between the auxiliary fields not only to define composite states but also to compute the effective action.

hep-th↗

arXiv2020

Dirichlet boundary condition for the Lee-Wick-like scalar model

Lee-Wick-like scalar model near a Dirichlet plate is considered in this work. The modified propagator for the scalar field due to the presence of a Dirichlet boundary is computed, and the interaction between the plate and a point-like scalar charge is analysed. The non-validity of the image method is investigated and the results are compared with the corresponding ones obtained for the Lee-Wick gauge field and for the standard Klein-Gordon field.

hep-th↗

arXiv2019

Higgs Mechanism and Debye Screening in the Generalized Electrodynamics

In this work we study the Higgs mechanism and the Debye shielding for the Bopp-Podolsky theory of electrodynamics. We find that not only the massless sector of the Podolsky theory acquires a mass in both these phenomena, but also that its massive sector has its mass changed. Furthermore, we find a mathematical analogy in the way these masses change between these two mechanisms. Besides exploring the behaviour of the screened potentials, we find a temperature for which the presence of the generalized gauge field may be experimentally detected.

hep-th↗

arXiv2018

Reduction of order and Fadeev-Jackiw formalism in generalized electrodynamics

The aim of this work is to discuss some aspects of the reduction of order formalism in the context of the Fadeev-Jackiw symplectic formalism, both at the classical and the quantum level. We start by reviewing the symplectic analysis in a regular theory (a higher derivative massless scalar theory), both using the Ostrogradsky prescription and also by reducing the order of the Lagrangian with an auxiliary field, showing the equivalence of these two approaches. The interpretation of the degrees of freedom is discussed in some detail. Finally, we perform the similar analysis in a singular higher derivative gauge theory (the Podolsky electrodynamics), in the reduced order formalism: we claim that this approach have the advantage of clearly separating the symplectic structure of the model into a Maxwell and a Proca (ghost) sector, thus complementing the understanding of the degrees of freedom of the theory and simplifying calculations involving matrices.

hep-th↗

arXiv2018

Transition amplitude, partition function and the role of physical degrees of freedom in gauge theories

This work explores the quantum dynamics of the interaction between scalar (matter) and vectorial (intermediate) particles and studies their thermodynamic equilibrium in the grand-canonical ensemble. The aim of the article is to clarify the connection between the physical degrees of freedom of a theory in both the quantization process and the description of the thermodynamic equilibrium, in which we see an intimate connection between physical degrees of freedom, Gibbs free energy and the equipartition theorem. We have split the work into two sections. First, we analyze the quantum interaction in the context of the generalized scalar Duffin-Kemmer-Petiau quantum electrodynamics (GSDKP) by using the functional formalism. We build the Hamiltonian structure following the Dirac methodology, apply the Faddeev-Senjanovic procedure to obtain the transition amplitude in the generalized Coulomb gauge and, finally, use the Faddeev-Popov-DeWitt method to write the amplitude in covariant form in the no-mixing gauge. Subsequently, we exclusively use the Matsubara-Fradkin (MF) formalism in order to describe fields in thermodynamical equilibrium. The corresponding equations in thermodynamic equilibrium for the scalar, vectorial and ghost sectors are explicitly constructed from which the extraction of the partition function is straightforward. It is in the construction of the vectorial sector that the emergence and importance of the ghost fields are revealed: they eliminate the extra non-physical degrees of freedom of the vectorial sector thus maintaining the physical degrees of freedom.

hep-th↗

arXiv2018

BRST symmetry and fictitious parameters

Our goal in this work is to present the variational method of fictitious parameters and its connection with the BRST symmetry. Firstly we implement the method in QED at zero temperature and then we extend the analysis to GQED at finite temperature. As we will see the core of the study is the general statement in gauge theories at finite temperature, assigned by Tyutin work, that the physics does not depend on the gauge choices, covariant or not, due to BRST symmetry.

hep-th↗

arXiv2018

Radiative Corrections in GSDKP

We show explicit the first radiative correction for the vertex and photon-photon 4-point function in Generalized Scalar Duffin-Kemmer-Petiau Quantum Electrodynamcis (GSDKP), utilizing the dimensional regularization method, where the gauge symmetry is manifest. As we shall see one of the consequences of the study is that the DKP algebra ensures the functioning of theWard- Takahashi-Fradkin (WTF) identities in the first radiative corrections prohibiting certain ultraviolet (UV) divergences. This result leads us to ask whether this connection between DKP algebra, UV divergences, and quantum gauge symmetry (WTF) is a general statment.

physics.gen-ph↗

arXiv2015

Functional quantization of Generalized Scalar Duffin-Kemmer-Petiau Electrodynamics

The main goal of this work is to study systematically the quantum aspects of the interaction between scalar particles in the framework of Generalized Scalar Duffin-Kemmer-Petiau Electrodynamics (GSDKP). For this purpose the theory is quantized after a constraint analysis following Dirac's methodology by determining the Hamiltonian transition amplitude. In particular, the covariant transition amplitude is established in the generalized non-mixing Lorenz gauge. The complete Green's functions are obtained through functional methods and the theory's renormalizability is also detailed presented. Next, the radiative corrections for the Green's functions at $α$-order are computed; and, as it turns out, an unexpected $m_{P}$-dependent divergence on the DKP sector of the theory is found. Furthermore, in order to show the effectiveness of the renormalization procedure on the present theory, a diagrammatic discussion on the photon self-energy and vertex part at $α^{2}$-order are presented, where it is possible to observe contributions from the DKP self-energy function, and then analyse whether or not this novel divergence propagates to higher-order contributions. Lastly, an energy range where the theory is well defined: $m^{2}\ll k^{2}<m_{p}^{2}$ was also found by evaluating the effective coupling for the GSDKP.

hep-th↗