arXiv subjects

D. Bazeia

Publications and source records attributed to D. Bazeia.

At least 55 records · Page 3Linked to original sources

arXiv2023

Asymmetry engendered by symmetric kink-antikink scattering in a degenerate two-field model

In this paper we analyze the scattering process in a two-field model in $(1+1)$-dimensions, with the special property to have several topological solutions: i) one with higher rest mass, characterized by a nested defect (lump inside a kink), and ii) four others having lower rest mass, degenerated, and characterized by a kink inside kink. We investigate kink-antikink symmetric scattering, where the kink and antikink have higher rest mass and the same initial velocity modulus $v$. The output of scattering presents a wide range of behaviors, such as annihilation of the kink-antikink pair, the emission of radiation jets, the generation of oscillating pulses and the change of the topological sector. We show that the changing of the topological sector is favored, and only two of the four sectors are possible as outcomes. Moreover, despite the degeneracy in energy, the distribution of the final states is asymmetric in the phase space, being an effect of the presence of vibrational states.

hep-th↗

arXiv2023

Geometrically constrained kinklike configurations engendering long range, double exponential, half-compact and compact behavior

We describe a procedure that contributes to modify the asymptotic behavior of kinks in a model described by two real scalar fields. The investigation takes advantage of a first order formalism based on energy minimization to unveil how to modify the asymptotic profile of kinklike configurations. In particular, we show that the exponential tails of standard kinklike configurations can be smoothly modified to engender long range, double exponential, half-compact or compact behavior.

hep-th↗

arXiv2023

Scalar-tensor representation to $f(R,T)-$brane with Gauss-Bonnet gravity

In this paper, we generalize the analysis of the $f(R,T)-$brane via the inclusion of a term proportional to the Gauss-Bonnet invariant. We consider an action of the form $F(R,G,T)=f(R,T)+αG$, where $T$ is the trace of the stress-energy tensor, $R$ is the Ricci scalar, and $α$ is a real parameter that controls the contribution of the Gauss-Bonnet invariant $G$. We introduce the first-order formalism to obtain solutions for the source field of the brane in the special case where $f(R,T)=R+βT$ and illustrate its procedure with an application to the sine-Gordon model. We also investigate the general case of the $f(R,T)-$brane via the use of the scalar-tensor formalism, where we also use the first-order formalism to obtain solutions. Finally, we investigate the linear stability of the brane under tensor perturbations of the the modified Einstein's field equations. Our results indicate that the Gauss-Bonnet term may induce qualitatively different behaviors of the quantities on the brane, provided that its contribution is large enough.

gr-qc↗

arXiv2023

Localized scalar structures around static black holes

In this work we address a way to capture scalar field solutions on static spacetimes by using BPS formalism and relaxing the general covariance condition. We focus on configurations where the background geometry describes topological black holes and present both analytical and numerical solutions, in addition to discussing the use of conserved charges associated to such field configurations. The obtained solutions are radially stable and the zero-mode arising from the stability equation can be written analytically.

hep-th↗

arXiv2023

Cuscuta-Galileon Braneworlds

We investigate braneworlds modeled by topological solutions that arise from the so-called Cuscuta-Galileon model. We develop a first order framework and illustrate our procedure with the scalar field having the well-known hyperbolic tangent profile. We find conditions that must be imposed to the parameters of the model in order to have solutions connecting minima of the potential, with the brane constrained to interpolate Minkowski and anti de Sitter geometries. We also find solutions where the brane only interpolates anti de Sitter geometry. In both cases, the gravity sector of the brane is stable against small fluctuations of the metric.

hep-th↗

arXiv2023

Mechanism to induce geometric constriction on kinks and domain walls

We investigate scalar field theories in the multifield scenario, focusing mainly on the possibility to smoothly build internal structure and asymmetry for kinks and domain walls. The procedure requires the inclusion of an extra field which is associated to a function that modifies the dynamics of the other fields. We investigate minimum energy configurations, which support first order equations compatible with the equations of motion. The extra field allows a transition which is guided by a parameter that connects the standard solution to another one, geometrically constrained, mimicking the effects of geometrical constrictions in magnetic materials.

hep-th↗

arXiv2022

Manipulating the internal structure of Bloch walls

In this work, we describe a procedure to manipulate the internal structure of localized configurations of the Bloch wall type. We consider a three-field model and develop a first order formalism based on the minimization of the energy of the static fields. The results show that the third field may be decoupled and used to change the geometric arrangement of the Bloch wall, giving rise to a diversity of modifications of its internal structure. The procedure captures effects that goes beyond the standard situation and can be used in several applications of practical interest, in particular, for the study of the magnetization of magnetic materials at the nanometric scale.

hep-th↗

arXiv2022

Collisions of kinks in deformed $φ^4$ and $φ^6$ models

Two hyperbolic-deformed field theoretic models are discussed. In both of them, due to the effect of specific deformation function on the well known $φ^4$ and $φ^6$ models, their internal structure may change significantly. Unlike the $φ^4$ kinks solutions, which has only one internal mode in addition to its translational mode, the kinks of the hyperbolic-deformed $φ^4$ model can have several internal modes. Moreover, the deformation on the $φ^6$ model has other interesting features, because the kinks of the $φ^6$ model have only a zero mode and the deformation may cause the appearance of internal mode for both kink and antikink. The presence of the new internal modes modify the collisions which we explore in the present work. The deformation relies on a real parameter, which controls the number of internal modes, and we also study how the deformation parameter alter the mass of the kinks and the critical velocities involved in the collisions.

hep-th↗

arXiv2022

Electrically charged multi-field configurations

In this work we investigate the presence of electrically charged structures that are localized in two and three spatial dimensions. We use the Maxwell-scalar Lagrangian to describe several systems with distinct interactions for the scalar fields. The procedure relies on finding first order differential equations that solve the equations of motion and ensure stability of the corresponding minimum energy solutions. We illustrate the many possibilities in two and in three spatial dimensions, examining different examples of electrically charged solutions that engender internal structure

hep-th↗

arXiv2022

Multi-kink braneworld configurations in the scalar-tensor representation of $f(R,T)$ gravity

In this work we investigate the $f(R,T)$ brane in the scalar-tensor representation, where the solutions of the equations of motions for the source field engender topological defects with two-kink profiles. We use the first-order formalism to obtain analytical solutions for the source field of the brane and analyze how these solutions modify the structure of the auxiliary fields arising from the scalar-tensor representation of the theory. We found that when the model engenders two-kink solutions, the auxiliary fields are modified in order to allow for the appearance of an internal structure. In addition, the stability potential and zero mode also have their internal structure modified by two-kink solution.

gr-qc↗

arXiv2022

Generalized Jackiw-Teitelboim gravity in presence of Bloch brane-like models

We investigate generalized Jackiw-Teitelboim gravity, coupling the dilaton field with two scalar matter fields. We obtain the equations of motion of the fields and investigate the linear perturbation of the solutions in general. We study two specific situations that allow analytic solutions with topological behavior and check how the dilaton field, the warp factor and Ricci scalar behave. In particular, we have shown how the parameters can be used to modify the structure of the solutions. Moreover, the perturbations are in general described by intricate coupled differential equations, but in some specific cases we could construct the corresponding zero modes analytically.

hep-th↗

arXiv2022

New Results For Cuscuton Multi-Field Brane

We investigate braneworld models in the presence of the several scalar fields with generalized dynamics. A new mechanism to control the internal structure of brane in modified gravity is used to induce changes in the models in the presence of cuscuton dynamics. Examples with two- and three-field are considered, and we have found that the inclusion of the cuscuton can significantly alter the profile of the brane, causing unique changes in the warp factor, energy density, stability potential and the corresponding zero mode.

hep-th↗

arXiv2022

Bifurcation and chaos in one dimensional chains of small particles

This work deals with bifurcation and the chaotic behavior in one dimensional chains of small particles. We consider two distinct possibilities, one where the particles are modeled by a fourth-order potential which was already studied. We revisit this system and bring novelties concerning the presence of the three-armed star behavior and the study of the corresponding Lyapunov exponent. The other system is new, and there the particles are more involved and modeled by an eighth-order potential. We investigate this new system within the same approach, emphasizing the behavior of the orbits, the bifurcation profile and the corresponding Lyapunov exponent.

nlin.CD↗

arXiv2022

Mechanism to control the internal structure of thick brane

In this work we study braneworlds generated by several scalar fields. The investigation describes the necessary formalism to examine models and evaluate the conditions for the stability of the gravitational sector under linear perturbations. In particular, we develop a mechanism that help us investigate distinct situations controlled by two and by three fields, focusing on how the fields can be used to modify the internal structure of the brane.

hep-th↗

arXiv2022

Configurational entropy of skyrmions and half-skyrmions in planar magnetic elements

This works deals with the presence of localized planar structures in magnetic materials that admit integer or half-integer topological charge. We study models in which the internal disposition of magnetization is driven by a single parameter, that controls the topological charge density of the magnetic structure. In particular, we focus mainly on the configurational entropy of these skyrmions and half-skyrmions and show how to increase or diminish their informational capabilities.

cond-mat.soft↗

arXiv2022

Generalized Maxwell-Higgs vortices in models with enhanced symmetry

Topological vortices in relativistic gauge theories in flat three-dimensional spacetime are investigated. We consider the symmetry $\rm{U(1)}\times...\times \rm{U(1)}$, and for each $\rm{U(1)}$ subgroup, a complex scalar field transforming under its action is introduced, as well as generalized permeabilities through which the subsystems are coupled. We investigate in detail the features of static, finite energy solutions within this class of generalized Maxwell-Higgs models, and study the effect of the winding numbers in the magnetic properties of each subsystem. A BPS bound and the related first order equations are introduced for a large class of models. Finally, we present some specific models and solve their equations of motion to find solutions engendering many distinct features in relation to each other and to the standard Nielsen-Olesen vortex.

hep-th↗

arXiv2022

Models of modified $F(R,T)$ and cuscuton braneworld

This work deals with braneworld models in the presence of scalar fields in a five-dimensional warped geometry with a single extra dimension of infinite extent. We consider generalized models in the presence of the Ricci scalar, the trace of the stress-energy tensor and the cuscuton contribution. The models describe novel braneworld scenarios and the investigations consider distinct possibilities, from which we show how the brane may change to become thinner, although keeping gravitational stability and the gravity zero mode under strict control. Moreover, we did not identify any split behavior in the warp factor in the presence of the cuscuton and the trace of the stress-energy tensor.

hep-th↗

arXiv2022

Effects of Cuscuton dynamics on braneworld configurations in the scalar-tensor representation of $f\left(R,T\right)$ gravity

In this work we study braneworld configurations in the scalar-tensor representation of the $f\left(R,T\right)$ gravity theory in the presence of a Cuscuton term in the source field matter Lagrangian. We start by deriving the scalar-tensor representation of the theory and obtaining its respective equations of motion. We then introduce the standard metric for a flat braneworld model with one extra dimension for the general case of a $f\left(R,T\right)$ theory and study two different models for the source field. Given the complexity of the field equations, these solutions are obtained numerically. In these cases, the Cuscuton term effectively amplifies the effect, by increasing the height of the stability potential barrier and, consequently, the depth of the minimum of the graviton zero-mode on the brane. Finally, we study the particular cases of $F(R)+T$ and $R+G\left(T\right)$, for which only the scalar fields $φ$ or $ψ$ are present, respectively, and we prove that the presence of the scalar field $φ$ is essential in the development of internal structure on the brane.

gr-qc↗