The signature of dark energy perturbations in galaxy cluster surveys

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

Study of a degenerate dipolar Fermi gas of Dy-161 atoms

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

Universal aspects of light halo nuclei

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

Towards a hybrid compactification with a scalar-tensor global cosmic string

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Self-trapping of a binary Bose-Einstein condensate induced by interspecies interaction

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

Spherical collapse in chameleon models

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effective potential of two coupled binary matter wave bright solitons with spatially modulated nonlinearity

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

A sistemática incompreensão da teoria quântica e as dificuldades dos professores na introdução da Física Moderna e Contemporânea no Ensino Médio

O objetivo desta pesquisa é avaliar a proposta de introdução da Física Moderna e Contemporânea no Nível Médio da Educação Básica. Parte-se do pressuposto de que os professores assumem, às vezes até subconscientemente, que a teoria base da FMC é incompreensível. Investigamos, em 2007, os discursos de cinco professores de Física de um município da região Nordeste, visando compreender as possibilidades desses professores introduzirem a FMC em suas aulas de Física e em que medida estas possibilidades estão associadas às suas formações profissionais. Para a construção e análises dos discursos pautamo-nos na Análise de Discurso Francesa e em referenciais da Teoria Crítica da Educação. Constatamos que apesar de atribuírem papel relevante à introdução da FMC no Nível Médio, os professores não estão encarando este desafio.

BOUSSINESQ-TYPE SYSTEM OF EQUATIONS IN THE BENARD-MARANGONI SYSTEM

A system of coupled evolution equations for the bulk velocity and the surface displacement is found to govern the long-wavelength perturbations in a Benard-Marangoni system. This system of equations, involving nonlinearity, dispersion, and dissipation, is a generalization of the usual Boussinesq system.

Resonance in positron-helium scattering at medium energy

A narrow S-wave resonance has been found in the positron-helium system at about 30 eV, using the close-coupling approach, in excitation and rearrangement cross sections to He(1s2s), He(1s2p), Ps(1s) and Ps(2s) states by employing different combinations of the following basis functions: He(1s1s), He(1s2s), He(1s2p), Ps(1s) and Ps(2s), where Ps stands for the positronium atom.

Application of renormalization to potential scattering

A recently proposed renormalization scheme can be used to deal with nonrelativistic potential scattering exhibiting ultraviolet divergence in momentum space. A numerical application of this scheme is made in the case of potential scattering with r(-2) divergence for small r, common in molecular and nuclear physics, by using cut-offs in momentum and configuration spaces. The cut-off is finally removed in terms of a physical observable and model-independent result is obtained at low energies. The expected variation of the off-shell behaviour of the t-matrix arising from the renormalization scheme is also discussed.

RESULTS FROM THE SLD BARREL CRID DETECTOR

We report on operational experience with an experimental performance of the SLD barrel Cherenkov Ring Imaging Detector from the 1992 and 1993 physics runs. The liquid (C6F14) and gas (C5F12) radiator recirculation systems have performed well, and the drift gas supply system has operated successfully with TMAE for three years. Cherenkov rings have been observed from both the liquid and gas radiators. The number and angular resolution of Cherenkov photons have been measured, and found to be close to design specifications.

Podolsky's higher-order electromagnetism from first principles

Podolsky's higher-order field equations are obtained by generalizing the laws of Podolsky's electrostatics, which follow from Coulomb's generalized law and superposition, to be consistent with special relativity. In addition, it is necessary to take into account the independence of the observed charge of a particle on its speed. It is also shown that the gauge-independent term concerning the Feynman propagator for Podolsky's generalized electrodynamics has a good ultraviolet behaviour at the expense of a negative metric massive ghost which, contrary to what is currently assumed in the literature, is non-tachyonic. A brief discussion on Podolsky's characteristic length is presented as well.

DIRAC CONFINEMENT BY A VARIATIONAL APPROACH

An analytical approximate method for the Dirac equation with confining power law scalar plus vector potentials, applicable to the problem of the relativistic quark confinement, is presented. The method consists in an improved version of a saddle-point variational approach and it is applied to the fundamental state of massless single quarks for some especial cases of physical interest. Our treatment emphasizes aspects such as the quantum-mechanical relativistic Virial theorem, the saddle-point character of the critical point of the expectation value of the total energy, as well as the Klein paradox and the behaviour of the saddle-point variational energies and wave functions.

THE GREEN-FUNCTION IN THE BLOCH-NORDSIECK MODEL FOR QED(3)

The electron Green's function is obtained in the Bloch-Nordsieck approximation of three-dimensional QED. Dimensional regularization is used in the intermediate stages of calculation.