SEMINÁRIO DE FÍSICA ESTATÍSTICA - DFGE
"Complexity and Criticality"
Kim Christensen, Imperial College, Londres
22 de abril, terça-feira, Ed. Principal do IFUSP, Ala 1, sala 2
04, às 13h
Complexity is a rapidly developing field at the forefront of many areas of science.
In this talk, complexity refers to the repeated application of simple rules that gives
rise to emergent behaviour not encoded in the rules themselves. Criticality refers to
the behaviour of systems at a phase transition where no characteristic scales exist
and where the many constituent microscopic "parts" give rise to macroscopic phenomena
that cannot be understood by considering the laws obeyed by a single part alone. The
key concepts of complexity and criticality will be introduced and explored. From a
complexity point of view it will be suggested that avalanches in granular media,
earthquakes in the crust of the earth, and rainfall in the atmosphere, have a common
basis.
Reference.: "Complexity and Criticality", K. Christensen and N.R. Moloney,
Imperial College Press (2005).
SEMINÁRIOS DO DEPARTAMENTO DE FÍSICA
DOS MATERIAIS E MECÂNICA
"Atomic Scale Analysis of Impurity Wavefunctions in III/V
Semiconductors by Cross-Sectional Scanning Tunneling Microscopy"
Prof. Dr. Paul M. Koenraad, Eindhoven University of Technology the
Netherlands
22 de abril, terça-feira, Sala de Seminários José
Roberto Leite, Ed. Alessandro Volta (bloco C), às 16h
Recently, we have shown that cross-sectional STM can be used to manipulate the
charge state of a single impurity embedded in a semiconductor material and that it
can resolve the shape of the wavefunction of a single carrier bound to an impurity.
Such information about the wavefunction is very valuable as it allows a direct
identification of the character of the electronic state and an analysis of the
interaction between impurities. We will review our recent results on charge manipulation
and wavefunction imaging of single impurities, strained impurities and interacting
pairs of impurities.
"Spin Polarization in Resonant Tunneling Diodes"
Profa. Dra. Yara Galvão Gobato, Departamento de
Física da Universidade Federal de São Carlos, SP
23 de abril, quarta-feira, Sala de Seminários José
Roberto Leite, Ed. Alessandro Volta (bloco C) às 16h
The understanding of the physics governing the dynamics of spin-polarized carriers
in semiconductor structures is fundamental for the development of spin-based devices.
In the last years, several systems have been proposed for spin-based devices, including
magnetic metal/semiconductor junctions, all metallic devices and all semiconductor
systems. However, for some systems the change of the polarization requires the use
of an external magnetic field to change the contact magnetization. For device
applications, it would be desirable to have devices where the spin character of the
injected or detected electrons could be voltage selected. One possible approach to
achieve this goal is based on resonant tunneling diodes (RTD). Recently, the successful
operation of II-VI semimagnetic resonant tunneling diodes as voltage-controlled electron
spin-polarized filters was reported as the first step of a voltage controlled spin
filter. In this seminary, we will discuss some experimental results of hole and
electron spin polarization in non-magnetic III-V RTDs. The spin-dependent tunneling
of the carriers is studied by analyzing the current-voltage characteristics (I(V))
and the right (σ+) and left (σ-) circular polarized
emissions from the contact layers and from the quantum well (QW) as a function of
the applied bias under magnetic field parallel to the tunnel current. Our results
are interpreted as evidence of voltage-controlled tunneling transport through spin
polarized levels in the non-magnetic structure.
SEMINÁRIO DO DEPARTAMENTO DE
FÍSICA APLICADA
"John M. Greene 1928-2007"
Prof. Dr. Philip J. Morrison (Institute of Fusion Studies, University of Texas at Austin)
24 de abril, quinta-feira, Ed. Basilio Jafet, Sala 105, IFUSP, às 14h
John M. Greene passed away on October 22, 2007 in San Diego, California. He was an
unusually creative scientist who worked in plasma physics, nonlinear dynamics, and other
fields. His work was characteristically original, of great depth and clarity, concise,
mathematically clean, and broadly applicable. In this talk I will highlight some of his
research, including: BGK modes, exact nonlinear solutions of the Vlasov-Poisson system;
the inverse scattering transform, a method of solution for the KdV equation (and others)
via a remarkable transformation; Greene's residue criterion, which describes how invariant
tori, e.g. magnetic surfaces, break; and other work on Hamiltonian systems.
CONVITE À FÍSICA
Colóquios dedicados ao público geral, em especial aos alunos ingressantes da USP.
Organizados pelo Departamento de Física Matemática
"A Teoria da Informação"
Prof. Dr. Nestor Caticha, IFUSP
23 de abril, quarta-feira, Auditório Abrahão de Moraes, IFUSP, às 18h
Home-page: http://fma.if.usp.br/convite
A teoria da informação é um dos ramos da Matemática Aplicada com maior número de aplicações, nas mais diversas áreas. Essas áreas vão desde a inferência estatística, tecnologia da informação, processamento de imagens, neurolinguística, neurobiologia e até buracos negros. Nesse colóquio vamos apresentar as principais idéias e aplicações da Teoria da Informação.
Os Organizadores
ATIVIDADES DA SEMANA
3ª. FEIRA, 22.04.2008
Seminário de Física Estatística - DFGE
"Complexity and Criticality"
Kim Christensen, Imperial College, Londres
Ed. Principal, Ala 1, sala 204, às 13h
Seminário do Laboratório de Cristalografia - DFAP
"Mesoporous materials from Evaporation Induced Self-Assembly Routes"
Dr. Galo Soler-Illia (Grupo de Nanomateriales, Gerencia de Química, CNEA, Centro Atómico Constituyentes, Argentina)
Auditório Norte, IFUSP, às 14h
Seminário do Departamento de Física dos Materiais e Mecânica
"Atomic Scale Analysis of Impurity Wavefunctions in III/V Semiconductors by Cross-Sectional Scanning Tunneling Microscopy"
Prof. Dr. Paul M. Koenraad, Eindhoven University of Technology the Netherlands
Sala de Seminários José Roberto Leite, Ed. Alessandro Volta (bloco C), às 16h
Seminário do Grupo de Hádrons e Física Teórica (GRHAFITE)
"Um "cutoff" infravermelho natural para as interações fortes?"
Professor Doutor Adriano Antonio Natale, IFT, UNESP
Ed. Principal do IFUSP, Ala 2, Sala 335, às 17h
4ª. FEIRA, 23.04.2008
Seminário do Departamento de Física Nuclear
"Atividades desenvolvidas pelo Grupo de Apoio Pedagógico Central"
Prof. Raphael Liguori Neto, DFNC, IFUSP,
Sala de Seminários do DFN (Linac), IFUSP, às 16h
Seminário do Departamento de Física dos Materiais e Mecânica
"Spin Polarization in Resonant Tunneling Diodes"
Profa. Dra. Yara Galvão Gobato, Departamento de Física da Universidade Federal de São Carlos, SP
Sala de Seminários José Roberto Leite, Ed. Alessandro Volta (bloco C), às 16h
Convite à Física
"A Teoria da Informação"
Prof. Dr. Nestor Caticha, IFUSP
Auditório Abrahão de Moraes, IFUSP, às 18h
5ª. FEIRA, 24.04.2008
Seminário de Caos - DFAP
"John M. Greene 1928-2007"
Prof. Dr. Philip J. Morrison (Institute of Fusion Studies, University of Texas at Austin)
Ed. Basílio Jafet, Sala 105, IFUSP, às 14h
Colóquio
"Processos dinâmicos em redes complexas"
Marcus A. M. de Aguiar, IFGW, UNICAMP
Auditório Norte, IFUSP, às 16h
6ª. FEIRA, 25.04.2008
Seminário do GFCx - DFEP
"Influência da adsorção na impedância de uma célula eletrolítica"
Dr. Fernando Batalioto, IFUSP
Auditório Adma Jafet, IFUSP, às 14h
Seminário do Grupo de Física Molecular e Modelagem - DFGE
"Simulação computacional do espectro eletrônico do fenol em água"
Rafael C. Barreto, Doutorando do IFUSP
Ed. Principal do IFUSP, Ala 1, Sala de Seminários do DFGE, às 16h
B I F U S P - Uma publicação semanal do Instituto de Física da USP
Editor: Prof. Dr. Antônio Domingues dos Santos
Secretária: Silvana Sampaio
Textos e informações assinados são de responsabilidade de seus autores
São divulgadas no BIFUSP as notícias encaminhadas até 4a feira,
às 12h, impreterivelmente
Tel: 3091-6900 - Fax: 3091-6701 - e-mail:
bifusp@if.usp.br - Home page:
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