Bound states of bosons and fermions in a mixed vector-scalar coupling with unequal shapes for the potentials

The Klein - Gordon and the Dirac equations with vector and scalar potentials are investigated under a more general condition, V(v) + V(s) = constant. These intrinsically relativistic and isospectral problems are solved in the case of squared hyperbolic potential functions and bound states for either particles or antiparticles are found. The eigenvalues and eigenfuntions are discussed in some detail and the effective Compton wavelength is revealed to be an important physical quantity. It is revealed that a boson is better localized than a fermion when they have the same mass and are subjected to the same potentials.

Nonpolynomial potentials with deformable topological structures

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Spin and pseudospin symmetries in the Dirac equation with central Coulomb potentials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microstructural Characterization of Ti-6Al-7Nb Alloy After Severe Plastic Deformation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of Deformation, Mass Loss, and Roughness of Different Metal Burs After Osteotomy for Osseointegrated Implants

Purpose: This study used bovine ribs to comparatively assess the deformation, roughness, and mass loss for 3 different types of surface treatments with burs, used in osteotomies, for the installation of osseointegrated implants.Materials and Methods: The study used 25 bovine ribs and 3 types of helical burs (2.0 mm and 3.0 mm) for osteotomies during implant placement (a steel bur [G1], a bur with tungsten carbide film coating in a carbon matrix [G2], and a zirconia bur [G3]), which were subdivided into 5 subgroups: 1, 2, 3, 4, and 5, corresponding to 0, 10, 20, 30, and 40 perforations, respectively. The surface roughness (mean roughness [Ra], partial roughness, and maximum roughness) and mass (in grams) of all the burs were measured, and the burs were analyzed in a scanning electron microscope before and after use. Data were tabulated and statistically analyzed by use of the Kruskal-Wallis test, and when a statistically significant difference was found, the Dunn test was used.Results: There was a loss of mass in all groups (G1, G2, and G3), and this loss was gradual, according to the number of perforations made (1, 2, 3, 4, and 5). However, this difference was not statistically significant (P < .05). Regarding the roughness, G3 presented an increase in Ra, partial roughness, and maximum roughness (P < .05) compared with G2 and an increase in Ra compared with G1. There was no statistically significant difference (P > .05) between G1 and G2. The scanning electron microscopy analysis found areas of deformation in all the 2.0-mm samples, with loss of substrates, and this characteristic was more frequent in G3.Conclusions: The 2.0-mm zirconia burs had a greater loss of substrates and abrasive wear in the cutting area. They also presented an increased roughness when compared with the steel and the tungsten carbide coating film in carbon matrix. There was no statistically significant difference (P < .05) between G1 and G2 in any mechanical test carried out. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:e608-e621, 2012

The Hierarchy of Hamiltonians for a Restricted Class of Natanzon Potentials

The restricted class of Natanzon potentials with two free parameters is studied within the context of Supersymmetric Quantum Mechanics. The hierarchy of Hamiltonians and a general form for the superpotential is presented. The first members of the superfamily are explicitly evaluated.

The Influence of Solutes on the Enthalpy/Entropy Change of the Actinomycin D Binding to DNA: Hydration, Energy Compensation and Long-Range Deformation on DNA

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

CP violation conditions in N-Higgs-doublet potentials

Conditions for CP violation in the scalar potential sector of general N-Higgs-doublet models are analyzed from a group theoretical perspective. For the simplest two-Higgs-doublet model potential, a minimum set of conditions for explicit and spontaneous CP violation is presented. The conditions can be given a clear geometrical interpretation in terms of quantities in the adjoint representation of the basis transformation group for the two doublets. Such conditions depend on CP-odd pseudoscalar invariants. When the potential is CP invariant, the explicit procedure to reach the real CP-basis and the explicit CP transformation can also be obtained. The procedure to find the real basis and the conditions for CP violation are then extended to general N-Higgs-doublet model potentials. The analysis becomes more involved and only a formal procedure to reach the real basis is found. Necessary conditions for CP invariance can still be formulated in terms of group invariants: the CP-odd generalized pseudoscalars. The problem can be completely solved for three Higgs-doublets.

Discretizing the deformation parameter in the su(q)(2) quantum algebra

Inspired in recent works of Biedenham [1, 2] on the realization of the q-algebra su(q)(2), We show in this note that the condition [2j + 1](q) = N-q(j) = integer, implies the discretization of the deformation parameter alpha, where q = e(alpha). This discretization replaces the continuum associated to ct by an infinite sequence alpha(1), alpha(2), alpha(3),..., obtained for the values of j, which label the irreps of su(q)(2). The algebraic properties of N-q(j) are discussed in some detail, including its role as a trace, which conducts to the Clebsch-Gordan series for the direct product of irreps. The consequences of this process of discretization are discussed and its possible applications are pointed out. Although not a necessary one, the present prescription is valuable due to its algebraic simplicity especially in the regime of appreciable values of alpha.

Dynamical localization of matter-wave solitons in managed barrier potentials

The bright matter-wave soliton propagation through a barrier with a rapidly oscillating position is investigated. The averaged-over rapid oscillations Gross-Pitaevskii equation is derived, where the effective potential has the form of a finite well. Dynamical trapping and quantum tunneling of the soliton in the effective finite well are investigated. The analytical predictions for the effective soliton dynamics is confirmed by numerical simulations of the full Gross-Pitaevskii equation.

Darboux-Egoroff metrics, rational Landau-Ginzburg potentials and the Painleve VI equation

We present a class of three-dimensional integrable structures associated with the Darboux-Egoroff metric and classical Euler equations of free rotations of a rigid body. They are obtained as canonical structures of rational Landau-Ginzburg potentials and provide solutions to the Painleve VI equation.

Renormalization of singular potentials and power counting

We use a toy model to illustrate how to build effective theories for singular potentials. We consider a central attractive 1/r(2) potential perturbed by a 1/r(4) correction. The power-counting rule, an important ingredient of effective theory, is established by seeking the minimum set of short-range counterterms that renormalize the scattering amplitude. We show that leading-order counterterms are needed in all partial waves where the potential overcomes the centrifugal barrier, and that the additional counterterms at next-to-leading order are the ones expected on the basis of dimensional analysis. (C) 2008 Elsevier B.V. All rights reserved.

Spontaneous symmetry breaking of Bose-Fermi mixtures in double-well potentials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nonlinear two-field models from orbit equation deformations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rapidly varying boundaries in equations with nonlinear boundary conditions. The case of a Lipschitz deformation

We analyze the behavior of solutions of nonlinear elliptic equations with nonlinear boundary conditions of type partial derivative u/partial derivative n + g( x, u) = 0 when the boundary of the domain varies very rapidly. We show that the limit boundary condition is given by partial derivative u/partial derivative n+gamma(x) g(x, u) = 0, where gamma(x) is a factor related to the oscillations of the boundary at point x. For the case where we have a Lipschitz deformation of the boundary,. is a bounded function and we show the convergence of the solutions in H-1 and C-alpha norms and the convergence of the eigenvalues and eigenfunctions of the linearization around the solutions. If, moreover, a solution of the limit problem is hyperbolic, then we show that the perturbed equation has one and only one solution nearby.