Metastable States
Mostrando 1-12 de 44 artigos, teses e dissertações.
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1. IMPLATAÇÃO DE UM ESPECTRÔMETRO DE ESTADOS METAESTÁVEIS DE ALVOS GASOSOS
O estudo de ressonâncias, através de estados metaestáveis pelo impacto de elétrons, permite observar estruturas bem definidas nos espectros, gerando informações diretas sobre as energias de formação das ressonâncias, bem como suas formas e larguras. A investigação destas ressonâncias é muito importante em vários ramos da ciência, possuindo in�
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/06/2009
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2. A simple way to avoid metastable configurations in the density-matrix renormalization-group algorithms
We use the spin-1 Heisenberg chain with periodic boundary conditions to ilustrate that the systems get stuck in metastable configurations only when the density-matrix renormalization-group algorithm start with small number of states m. We also show that the convergence of the energies have a huge improvement if we start the algorithm with a large number of s
Brazilian Journal of Physics. Publicado em: 2009-09
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3. Nuclear problems in astrophysical q-plasmas and environments
Experimental measurements in terrestrial laboratory, space and astrophysical observations of variation and fluctuation of nuclear decay constants, measurements of large enhancements in fusion reaction rate of deuterons implanted in metals and electron capture by nuclei in solar core indicate that these processes depend on the environment where they take plac
Brazilian Journal of Physics. Publicado em: 2009-08
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4. A study of cooling in a system with several ground states. / Estudo do resfriamento em um sistema com múltiplos estados fundamentais
We study a coupled two level systems as a model that imitate the behavior of supercooled liquids that become structural glasses under cooling. In the equilibrium the model shows a liquid phase and a crystalline phase with many grouond states. The model is defined on a square lattice and to each site a stochastic Ising variable is associated. The feature that
Publicado em: 2007
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5. Propriedades de equilÃbrio e de transporte da matÃria de vÃrtices em nanoestruturas supercondutoras
In the present thesis, we study theoretically the equilibrium properties and dynamics of the vortex matter in two classes of nanostructured superconductors: (i) mesoscopic samples, with dimensions comparable with the penetration depth; and (ii) films with periodic array of artificial traps. In both cases, the vortex lattice symmetry is strongly dependent on
Publicado em: 2007
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6. Emergence of complex spatio-temporal order in nonlinear field theories
We investigate the emergence of time-dependent nonperturbative configurations during the evolution of nonlinear scalar field models with symmetric and asymmetric double-well potentials. Complex spatio-temporal behavior emerges as the system seeks to establish equipartition after a fast quench. We show that fast quenches may dramatically modify the decay rate
Brazilian Journal of Physics. Publicado em: 2006-12
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7. Photoquenching indications of a thermally triggered transition between two different EL2 metastable states in GaAs
In this work we report the observation of two different EL2 metastable states in GaAs and the effect of the optical/thermal history of the sample on the behavior of the photoquenching kinetics. In one thermal/optical preparation, the photoquenching curve presented two time constants that have already been interpreted as an indication of two different metasta
Brazilian Journal of Physics. Publicado em: 2006-06
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8. Production of 1s2s2p4P states by transfer-loss cascades in O5+ collisions with he and H2 targets
Single differential cross-sections for transfer-loss (TL) leading to the production of O5+(1s2s³S)nl4L states were computed for 0.2-1.2 MeV/u collisions of O5+(1s²2s) ions with He and H2 targets. At these collision energies, 1s loss is significant and electron transfer to n = 3-4 levels is dominant. Furthermore, due to spin conservation, quartet states can
Brazilian Journal of Physics. Publicado em: 2006-06
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9. Systems Biology: an information-theoretic-based thermo-statistical approach
Systems Biology (system-level understanding in biological science), from the physical-chemical point of view, is involved with irreversible thermodynamics and nonlinear kinetic theory of open systems which are founded on nonequilibrium statistical mechanics. We describe a modern thermo-statistical approach for dealing with complex systems, in particular biol
Brazilian Journal of Physics. Publicado em: 2004-06
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10. Estudo QSAR de inibidores da secreção gastrica e simulação molecular da inibição
O estudo QSAR de inibidores da secreção gástrica e simulação molecular da inibição consiste em quatro fases. Na fase um busca-se validação dos métodos de simulação de solvatação. Na fase dois, a elaboração de modelos de relações quantitativas entre estrutura química e atividade biológica (QSAR) para compostos moduladores da secreção gá
Publicado em: 2004
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11. Modelos de vidros de spin com interações de ordem alta. / Spin glasses models with high-order interactions.
The statistical properties of the local optima (metastable states) of the infinite range Ising spin glass with p-spin interactions in the presence of an external magnetic field h are investigated analytically. The average number of optima as well as the typical overlap between pairs of identical optima are calculated for general p. For p > 2 and small h w
Publicado em: 2000
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12. Information processing in synchronous neural networks / Processamento de informações em redes de neurônios sincronas
Spin glasses are very complex systems characterized by a huge number of stable and metastable states. If we identify each state with a memorized information then spin glasses may be used as associative or content addressable memories. This spin glass model is then called a neural network. In this work we study the thermodynamics and some dynamical aspects of
Publicado em: 1988