Browsing by Author Centro Brasileiro de Pesquisas Físicas (CBPF)

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CBPF, publicação de divulgação científica do Centro Brasileiro de Pesquisas Físicas : na vanguarda da pesquisa-Centro Brasileiro de Pesquisas Físicas (CBPF)Esta publicação tem o objetivo de mostrar o que se faz hoje no CBPF, uma das fábricas de fazer ciência de nosso país. Nela, você vai descobrir uma instituição multifacetada e dinâmica com linhas de pesquisa ricas e interligadas. Não faltarão indicadores da produção científica, além de dados sobre o programa de pós-graduação, pioneiro na área de física e entre os melhores do Brasil. Recordamos também a criação do CBPF, através de emocionantes depoimentos de seus fundadores, Cesar Lattes, José Leite Lopes e Jayme Tiomno. Como parte do recente processo de incorporação ao Ministério da Ciência e Tecnologia, o CBPF preparou detalhado relatório técnico. Tomando este por base, partimos agora para a divulgação de nosso trabalho para um público amplo, prestando, assim, contas à sociedade, que financia através dos impostos nossa instituição. Integrando uma tradição científica ímpar ao dinamismo das novas gerações de pesquisadores, o Centro Brasileiro de Pesquisas Físicas enfrenta os grandes desafios da atualidade, contribuindo para o desenvolvimento cientifico e tecnológico de nosso país.
Clifford algebras and the minimal representations of the 1D N-Extended supersymmetry algebraToppan, FrancescoCentro Brasileiro de Pesquisas Físicas (CBPF)The Atiyah-Bott-Shapiro classification of the irreducible Clifford algebra is used to derive general properties of the minimal representations of the 1D N-Extended Supersymmetry algebra (the $Z_2$-graded symmetry algebra of the Supersymmetric Quantum Mechanics) linearly realized on a finite number of fields depending on a real parameter t, the time.
José Leite Lopes: in memorianCaruso, Francisco; Lopes, José LeiteCentro Brasileiro de Pesquisas Físicas (CBPF)-
Minimal representations of supersymmetry and 1D N-extended sigma-modelsToppan, FrancescoCentro Brasileiro de Pesquisas Físicas (CBPF)The Atiyah-Bott-Shapiro classification of the irreducible Clifford algebra is used to derive general properties of the minimal representations of the 1D N-Extended Supersymmetry algebra (the $Z_2$-graded symmetry algebra of the Supersymmetric Quantum Mechanics) linearly realized on a finite number of fields depending on a real parameter t, the time.
A note on infraparticles and unparticlesSchroer, BertCentro Brasileiro de Pesquisas Físicas (CBPF)We remind the reader of the meaning and achievements of infraparticles which, although themselves not necessarily of zero mass, require the presence of zero mass in order get delocalized states with a singularity which dissolves the mass-shell in an inexorable way into the continuum and therefore renders the standard particle concept useless. These objects were recently rediscovered under the name unparticles The case of infraparticles also encompasses particle-like objects in conformal QFT when all multiparticle thresholds coalesce on top of each other and only the concept of a highly inclusive cross section survives of scattering theory. The infraparticle research has led to deep results and the recently discovered semiinfinite string-localized vectorpotentials have led to new interesting ideas of dealing with physical electrically charged states and a generalized scattering theory. We explain why unparticles are identical to the old infraparticles. Using this relation it is shown that unparticles/infraparticles cannot lead to a natural description of darkness of dark matter. A more radical scenario for darkness comes from semiinfinite string-localized vectorpotentials in a reformulated version of nonabelian gauge theory.
On the hydrogen atom via wigner-heisenberg algebraRodrigues, R. de Lima (Rafael)Centro Brasileiro de Pesquisas Físicas (CBPF)We extend the usual kustaanheimo-stiefel 4D - 3d mapping to study and discuss a constrained super-wigner oscillator in four dimensions. We show that the physical hydrogen atom is the system that emerges in the bosonic sector of the mapped 3d system.
2016_regimento_interno_cbpf.pdf.jpgRegimento interno do Centro Brasileiro de Pesquisas Físicas: 2016-Centro Brasileiro de Pesquisas Físicas (CBPF)-
2020_regimento_interno_cbpf.pdf.jpgRegimento interno do Centro Brasileiro de Pesquisas Físicas: 2020-Centro Brasileiro de Pesquisas Físicas (CBPF)-
2022_regimento_interno_cbpf.pdf.jpgRegimento interno do Centro Brasileiro de Pesquisas Físicas: 2022-Centro Brasileiro de Pesquisas Físicas (CBPF)-
Relativeca dopplera efekto ce unuforme akcelata movo - III: efeito doppler relativa em um movimento uniforme acelerado - IIIPaiva, Filipe de Moraes; Teixeira, Antônio Fernandes da FonsecaCentro Brasileiro de Pesquisas Físicas (CBPF)Ce special-relativeco ni detale priskribas lum-Doppleran efikon inter restanta lum-fonto kaj observanto kun rektlinia movado kaj konstanta propra akcelo -- Na relatividade especial, nós descrevemos detalhadamente o efeito Doppler luminoso entre uma fonte em repouso e um observador com movimento retilíneo e aceleração própria constante.
Self-Interacting Electromagnetic Fields and a Classical Discussion on the Stability of the Electric ChargeVelloso, Sergio de Oliveira; Helayel Neto, José Abdalla; Smith, Alexander Willian; Assis, L. P. G de (Leonardo Paulo Guimarães de Assis)Centro Brasileiro de Pesquisas Físicas (CBPF)The present work proposes a discussion on the self-energy of charged particles in the framework of nonlinear electrodynamics. We seek magnetically stable solutions generated by purely electric charges whose electric and magnetic fields are computed as solutions to the Born-Infeld equations. The approach yields rich internal structures that can be described in terms of the physical fields with explicit analytic solutions. This suggests that the anomalous field probably originates from a magnetic excitation in the vacuum due to the presence of the very intense electric field. In addition, the magnetic contribution has been found to exert a negative pressure on the charge. This, in turn, balances the electric repulsion, in such a way that the self-interaction of the field appears as a simple and natural classical mechanism that is able to account for the stability of the electron charge.
Stochastic quantization for complex actionsMenezes, Gabriel; Svaiter, Nami FuxCentro Brasileiro de Pesquisas Físicas (CBPF)We use the stochastic quantization method to study systems with complex valued path integral weights. We assume a Langevin equation with a memory kernel and Einstein's relations with colored noise. The equilibrium solution of this non-Markovian Langevin equation is analyzed. We show that for a large class of elliptic non-Hermitian operators acting on scalar functions on Euclidean space, which define different models in quantum field theory, converges to an equilibrium state in the asymptotic limit of the Markov parameter. Moreover, as we expected, we obtain the Schwinger functions of the theory.
SUSY shape-invariant hamiltonians for the generalized dirac-coulomb problemRodrigues, R. de Lima (Rafael); Vaidya, Arvind NarayanCentro Brasileiro de Pesquisas Físicas (CBPF)A spin 1/2 relativisc particle described by a general potential in terms of the sum of the coulomb potential with a lorentz scalar potential is investigated via supersymmetry in quantum mechanics
The three-dimensionality of the Universe : a reason for the existence of chemists and beyondCaruso., F.Brasil. Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC); Centro Brasileiro de Pesquisas Físicas (CBPF)A general sketch of how the problem of space dimensionality depends on Anthropic arguments is presented. In particular, the influence of three-dimensionality on the stability of the solar system and on the origin of life on Earth is reviewed. A new constraint on space dimensionality and on its invariance in a very large time and spatial scales is proposed.
Time and space deformations in special relativity and measuring unitsde Oliveira., Alfredo MarquesCentro Brasileiro de Pesquisas Físicas (CBPF)Change of clock rates and the deformation of solid bodies following relativistic transformation between inertial reference systems are discussed under the principles of the physical theory of measurements. Both, time dilation and contraction of rods, are interpreted as being the result of measurements done under different unit standards rather than as a consequence of any physical action born in relative motion. The choice of units is not arbitrary but fixed by metric information contained in a light signal observed under the conditions of the transverse Doppler effect.