Foreword

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Perspectives for an Elko phenomenology using monojets at the 14 TeV LHC

The aim of this work is to explore the possibility to discover a fermionic field with mass dimension one, the Elko field, in the 14 TeV Large Hadron Collider (LHC), in processes with missing energy and one jet. We explore the possibility of a triple coupling with the Higgs field, generating also a contribution to the Elko mass term, and suggest some possibilities for future studies in this field.

Local order and magnetic field effects on the electronic properties of disordered binary alloys in the quantum site percolation limit

Electronic properties of disordered binary alloys are studied via the calculation of the average Density of States (DOS) in two and three dimensions. We propose a new approximate scheme that allows for the inclusion of local order effects in finite geometries and extrapolates the behavior of infinite systems following finite-size scaling ideas. We particularly investigate the limit of the Quantum Site Percolation regime described by a tight-binding Hamiltonian. This limit was chosen to probe the role of short range order (SRO) properties under extreme conditions. The method is numerically highly efficient and asymptotically exact in important limits, predicting the correct DOS structure as a function of the SRO parameters. Magnetic field effects can also be included in our model to study the interplay of local order and the shifted quantum interference driven by the field. The average DOS is highly sensitive to changes in the SRO properties and striking effects are observed when a magnetic field is applied near the segregated regime. The new effects observed are twofold: there is a reduction of the band width and the formation of a gap in the middle of the band, both as a consequence of destructive interference of electronic paths and the loss of coherence for particular values of the magnetic field. The above phenomena are periodic in the magnetic flux. For other limits that imply strong localization, the magnetic field produces minor changes in the structure of the average DOS. © World Scientific Publishing Company.

Classical and quantum N = 1 super W∞-algebras

We construct higher-spin N = 1 superalgebras as extensions of the super-Virasoro algebra containing generators for all spins s ≥ 3/2. We find two distinct classical (Poisson) algebras on the phase superspace. Our results indicate that only one of them can be consistently quantized.

Effects of a mixed vector-scalar kink-like potential for spinless particles in two-dimensional space time

The intrinsically relativistic problem of spinless particles subject to a general mixing of vector and scalar kink- like potentials (similar to tanh gamma x) is investigated. The problem is mapped into the exactly solvable Sturm - Liouville problem with the Rosen - Morse potential and exact bounded solutions for particles and antiparticles are found. The behavior of the spectrum is discussed in some detail. An apparent paradox concerning the uncertainty principle is solved by recurring to the concept of effective Compton wavelength.

SU(3) breaking and annihilation effects in the η and η′ masses

The mass splitting of the pseudoscalar mesons η and η′ is approached by taking into account the SU(3)-flavor symmetry breaking and annihilation effects. An extended version of the Schwinger sum rule and a mixing angle equal to -19.51° are obtained.

Evaluation of effective nucleon-nucleon potential and description of α-cluster type nuclei in restricted dynamics approach

The application of the Restricted Dynamics Approach in nuclear theory, based on the approximate solution of many-particle Schrödinger equation, which accounts for all conservation laws in many-nucleon system, is discussed. The Strictly Restricted Dynamics Model is used for the evaluation of binding energies, level schemes, E2 and Ml transition probabilities as well as the electric quadrupole and magnetic dipole momenta of light a-cluster type nuclei in the region 4 ≤ A ≤ 40. The parameters of effective nucleonnucleon interaction potential are evaluated from the ground state binding energies of doubly magic nuclei 4He, 16O and 40Ca.

Limits on a strong electroweak sector from e(+)e(-)->gamma gamma+E at LEP2

We study the process e+e- γγνν̄ in the context of a strong electroweak symmetry breaking model, which can be a source of events with two photons and missing energy at LEP2. We investigate bounds on the model assuming that no deviation is observed from the standard model within a given experimental error.

Elaboração de um material didático aplicado ao ensino de física para utilização do experimento virtual da dupla fenda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O mirabolante mundo das partículas elementares: uma sequência didática para professores de física

Pós-graduação em Ensino de Física (mestrado profissional) - FCT

A comunicação como barreira à inclusão de alunos com deficiência visual em aulas de Física Moderna

This article is part of a study that seeks to understand the main barriers to the inclusion of visually   impaired   students   in   learning   Physics.   Analyzing  modern physics classes, we examine the difficulties in communication between teachers and visually impaired students. Our study emphasizes the analyses of empirical­sensory and semantic structures of speech, indicating factors that may hamper  students’ understanding in the classroom. We recommend alternative procedures that aim to facilitate the effective participation of students with visual impairment in the communication process, such as:  elimination of the interdependent   audiovisual structure and the exploration of the communicational potentialities of a speech based on empirical structures whose accessibility does not depend on visual skills.

Análisis del proceso inclusivo del alumno ciego en clases de Física Moderna

This paper is aimed at understanding which the most important difficulties and alternatives to include students with visual impairments in physics classes. It presents and discusses the difficulties and viabilities of having a born blind student effectively attend Modern Physics classes. Using content analysis, this experiment identifies 6 functional classes that might correspond to difficulties and 4 which refer to the viabilities. Therefore, the importance of appropriate communicative environments, the including role of the interactivity element, as well as the need for destitution of segregation environments inside classroom, are emphasized.

Contextos comunicacionales adecuados e inadecuados para la inclusión de alumnos con discapacidad visual en clases de física moderna

This article is inserted in a wider study that seeks to understand the main inclusion barriers in Physics classes for students with visual impairment It aims to understand which communication context favors or impedes the visually impaired student participation to the impairment visual student’s real participation in Modern Physics activities. The research defines, from the empirical-sensory and semantics structures, the languages used in the activities, as well as, the moment and the speech pattern in which those languages have been used. As a result, this study identifies a strong relation between the uses of the interdependent empirical structure audio-visual language in the non-interactive episodes of authority; a decrease of this structure use in the interactive episodes; the creation of education segregation environments within the clasroom and the frequent use of empirical tactile-hearing interdependent language structure in these environments. Moreover, the concept of «special educational need» is discussed and its inadequate use is analyzed. Suggestions are given for its correct use of «special educational need,» its inadequate use, giving suggestions for its correct use.

Nanotecnologia e nanociência em livros didáticos de física do nível médio: discursos sobre a tecnologia e a educação científica e tecnológica

In this contribution, we analyze conceptual approaches to nanotechnology and nanoscience in recent issues of secondary education of Brazilian physics textbooks. We analyzed fifteen collections of Physics textbooks of recent editions, however, only two books, belonging to different collections incorporate considerations about nanotechnology and nanoscience in their approaches. We focus our analysis on three aspects, namely: the place dedicated to approaches to nanoscience and nanotechnology, notions about technology and its contributions to critical scientific education. This is a qualitative research; it was used as conceptual approaches the Philosophy of Technology, The Discourse Analysis (DA) and Science, Technology, Society (STS) concepts. We found that in two examined textbooks the approaches to nanoscience and nanotechnology is a complementary description of modern physics, associated with quantum theory. In this context, the concepts of nanoscience and nanotechnology focus superficially in the genesis of the field and some possible areas of applications. It was not identified in all textbooks warnings about the potential risks to human health and the environment from the use of nanotechnology and nanoscience. We understand that textbooks approaches about nanotechnology and nanoscience round a instrumental technological perspective, however keep away from the scientific and technological critical education.

QUANTUM FIELD THEORY IN GRAPHENE

This is a short nontechnical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.