arXiv subjects

G. B. de Gracia

Publications and source records attributed to G. B. de Gracia.

At least 19 recordsLinked to original sources

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↗

arXiv2025

Spinor Adjoints, Gauge Invariance and a new Road to Sterile Neutrinos

In this work, we analyze the possibilities of certain gauge transformations regarding some specific spinorial dual structures. To this end, we define a general structure, which can be expressed in terms of discrete symmetry operators associated with parity, charge conjugation, and time reversal. To this end, we consider the demand of tensor covariance of the spinor bilinears under space-time transformations and also deep algebraic considerations such as the invertibility of the dual structure which guarantee that the physical information remains unchanged (respecting the Fierz-Pauli-Kofink identities), and so on. Later, we examine the global gauge freedom implicated by each choice of dual and point out the physical implications. The final goal is achieved by establishing a well-defined coupling between the Elko and standard model neutrinos in a prelude for a new formulation of the hypothetical so-called sterile neutrino.

hep-th↗

arXiv2024

On Wigner Degeneracy in Elko theory: Hermiticity and Dark Matter

In this paper, we provide a set of Hermitian interactions for quantum fields based on Elko, considering the recent achievements concerning the most general form of singular spinors and Wigner degeneracy. We consider Hermiticity and renormalizability a criterion to define the derivative Elko-Higgs interaction as the suitable candidate for a dark coupling. Then, the free parameters of the model are fixed by cosmological constraints on the dark matter abundance, bounds on the Higgs invisible decays, and limits on the electron-dark matter scattering mediated by the Higgs.

hep-ph↗

arXiv2024

Irreducible representations of the inhomogeneous Lorentz group with two-fold Wigner degeneracy

Not all complete set of spinors can be used as expansion coefficients of a quantum field. In fact, Steven Weinberg established the uniqueness of Dirac spinors for this purpose provided: (a) one paid due attention to the multiplicative phases for each of the spinors, and (b) one paired these to creation and annihilation operators in a specific manner. This is implicit in his implementation of the rotational symmetry for the spin half quantum field. Among the numerous complete set of spinors that are available to a physicist, Elko occupies a unique status that allows it to enter as expansion coefficients of a quantum field without violating Weinberg's no go theorem. How this paradigm changing claim arises is the primary subject of this communication. Weinberg's no go theorem is evaded by exploiting a uniquely special feature of Elko that allows us to introduce a doubling of the particle-antiparticle degrees of freedom from four to eight. Weinberg had dismissed this degeneracy on the ground that, "no examples are known of particles that furnish unconventional representations of inversions." Here we will find that this degeneracy, once envisioned by Eugene Wigner, in fact gives rise to a quantum field that has all the theoretical properties required of dark matter.

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↗

arXiv2024

Duality as a Method to Derive a Gauge Invariant Massive Electrodynamics and New Interactions

Taking into account the recent developments associated with duality in physics, this article is focused on investigating the properties of a tensor generalization of the electrodynamics dual to the standard vector model even considering the full radiative corrections. A discussion on duality is extended for non-linearly interacting models. The alternative tensor structure allows a new local self-interaction and also a partial gauge invariant mass term. In this way, the renormalization conditions, a new interaction, Ward-Takahashi identities for all the sets of gauge symmetries, and the Schwinger-Dyson quantum equations are carefully provided to consistently characterize the propagating modes of the quantum system. The possibility of this gauge invariant massive extension is considered from the perspective of a generalized Stueckelberg procedure for higher derivative systems.

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

On valley asymmetry in a topological interaction for quasi-particles

This paper is focused on investigating the effects of a statistical interaction for graphene-like systems, providing Haldane-like properties for topologically trivial lattices. The associated self-energy correction yields an effective next-nearest hopping, inducing the topological phase, whose specific solutions are scrutinized. In the case of an external magnetic field, it leads to a renormalized quasi-particle structure with generalized Landau levels and explicit valley asymmetry. A suitable tool for implementing such achievements is a judicious indefinite metric quantization, leading to advances in field theory foundations. Since the topological behavior is encoded in the radiative corrections, an unequivocal treatment using an integral representation is carefully developed.

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↗

arXiv2023

Renormalized Kalb-Ramond model: duality and generalized potential

Considering the recent advances, the weak correlation between the massive Kalb-Ramond and the Proca interacting models is investigated by means of a set of complementary quantum field techniques beyond the semi-classical approach. A consistent framework to discuss the abrupt degree of freedom variation in the massless limit is established. In this manner, the Stueckelberg procedure is generalized for the present case to derive Ward-Takahashi constraints. By adding couplings with fermionic matter fields, even the weak dual correlation is broken due to the explicit form of the radiative corrections. However, considering the master action approach, the fermionic 1(PI) functions of the Proca electrodynamics are reproduced in all orders of perturbation. A well-defined procedure to eliminate non-desirable modes emerging from quantum corrections is successfully applied for this model. Last, but not least, we prove that this structure can also provide a spin interaction which is relevant even at macroscopic distances, being a completion for a recently proposed confining potential. This is based on an interacting theory in compliance with renormalizability.

hep-th↗

arXiv2022

Fermionic dark matter interaction with the photon and the proton in the quantum field-theoretical approach and generalizations

Mass dimension one quantum fields, constructed upon eigenspinors of the charge conjugation operator with dual helicity (ELKO), are prime candidates to describe dark matter. Their interaction with the photon and the proton, in scattering processes, are here explored and discussed, using both the standard QFT with a Maxwell gauge field and a generalized QFT also involving a Podolsky gauge sector. Renormalization and radiative corrections are analyzed in the ELKO setup, in the context of a generalized spinor dual and the twisted conjugation, both yielding unitarity. Several applications are scrutinized, involving the inherent darkness underlying ELKO construction and galaxies rotation curves, the non-relativistic potential regime, and the Møller-like scattering involving ELKO.

hep-th↗

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↗

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↗

arXiv2019

Duality and Self-duality of the Spin-1 Model in the Covariant Operator Formalism

We perform the covariant operator quantization of the spin-$1$ model in $2+1$ spacetime dimensions to rigorously establish its dualities. For this purpose, the Kugo-Ojima-Nakanishi formalism, based on an indefinite metric Hilbert space in the Heisenberg picture, is used. We show that it is possible to extract a massive physical excitation constructed from a linear combination of the vector field $A_μ$ and the $B$-field. In turn, we also show that this excitation generates the Maxwell-Chern-Simons theory. This is achieved by exploring the two-point function of the vector field.

hep-th↗

arXiv2019

Dynamical mass generation in QED$_3$: A non-perturbative approach

In this work, we provide a non-perturbative description of the phenomenon of dynamical mass generation in the case of quantum electrodynamics in $2+1$ dimensions. We will use the Kugo-Ojima-Nakanishi formalism to conclude that the physical Hilbert space of the asymptotic photon field is the same as that of the Maxwell-Chern-Simons.

hep-th↗

arXiv2017

The spin jumping in the context of a QCD effective model

The tensor formulation for the effective theory of QCD vector ressonances, whose model we denote by TEVR, is given by an antisymmetric tensor field and describes spin 1 particles. Our goal is to show, by diferent approaches, that the Abelian version of this model presents the so called "spin jumping" when we consider its massless limit. Classically we find, by the use of the equations of motion and the Hamiltonian constraint analysis, that the massive phase of the model describes spin 1 particles while its massless phase describes spin 0 particles. By the quantum point of view we derive these conclusions via tree level unitarity analysis and the master action approach.

hep-th↗

arXiv2017

Hamilton-Jacobi analysis of the four dimensional BF model with cosmological term

In this work we perform the Hamilton-Jacobi constraint analysis of the four dimensional Background Field (BF) model with cosmological term. We obtain the complete set of involutive Hamiltonians that guarantee the integrability of the system and identify the reduced phase space. From the fundamental differential we recover the equations of motion and obtain the generators of the gauge and shift transformations.

hep-th↗

arXiv2016

Simple prescription for computing the nonrelativistic interparticle potential energy related to dual models

Following a procedure recently utilized by Accioly et al. to obtain the D-dimensional interparticle potential energy for electromagnetic models in the nonrelativistic limit, and relaxing the condition assumed by the authors concerning the conservation of the external current, the prescription found out by them is generalized so that dual models can also be contemplated. Specific models in which the interaction is mediated by a spin-0 particle described first by a vector field and then by a higher-derivative vector field, are analyzed. Systems mediated by spin-1 particles described, respectively, by symmetric rank-2 tensors, symmetric rank-2 tensors augmented by higher derivatives, and antisymmetric rank-2 tensors, are considered as well.

hep-th↗