Hamiltonian Systems
Mostrando 13-24 de 82 artigos, teses e dissertações.
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13. Confinamento de partículas quânticas a curvas do espaço
In this work we study dimensional reductions in some quantum systems; such reductions occur due to confinement of the particle from a tube in space to a curve. Our main goal is to find the effective hamiltonian operator that describes the motion of the particle after confinement. We consider three particular situations. (1) In the first situation, we study a
Publicado em: 2010
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14. O sombreamento de trajetórias no mapa padrão
Os cálculos numéricos envolvendo as soluções de um sistema matemático apresentam ruído em razão dos erros de truncamento e arredondamento efetuados a cada passo. Se o sistema dinâmico apresentar caos, então estes erros são amplificados. Os sistemas dinâmicos hamiltonianos podem apresentar regiões disjuntas onde há ocorrência de caos e periodici
Publicado em: 2010
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15. NONLINEAR DYNAMICS, INSTABILITY AND CONTROL OF STRUCTURAL SYSTEMS WITH MODAL INTERACTION / DINÂMICA NÃO-LINEAR, INSTABILIDADE E CONTROLE DE SISTEMAS ESTRUTURAIS COM INTERAÇÃO MODAL
The aim of this thesis is to study the influence of coupled buckling modes on the static and particularly on the nonlinear dynamic behavior of structural components liable to buckling. For this, two discrete two degrees of freedom models known for their complex nonlinear behavior are selected: the well-known Augusti¿s model and a simplified model of cable-s
Publicado em: 2010
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16. Difusões em variedades de poisson / Poisson manifolds diffusions
O objetivo desse trabalho é estudar as equações de Hamilton no contexto estocástico. Sendo necessário para tal um pouco de conhecimento a cerca dos seguintes assuntos: cálculo estocástico, geometria de segunda ordem, estruturas simpléticas e de Poisson. Abordamos importantes resultados, dentre eles o teorema de Darboux (coordenadas locais) em varieda
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/08/2009
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17. The spin dynamics of molecular magnets beyond Kubo's linear response theory
The description of quantum dynamics of nanomagnets is a central issue in most applications proposed for those systems. In this paper, we put forward a modified perturbation approach to study the spin dynamics of a molecular magnet in the presence of time-dependent magnetic fields.The non-perturbed Hamiltonian H0, which defines the interaction picture, may be
Brazilian Journal of Physics. Publicado em: 2009-09
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18. Nonadditive entropy and nonextensive statistical mechanics -an overview after 20 years
Statistical mechanics constitutes one of the pillars of contemporary physics. Recognized as such - together with mechanics (classical, quantum, relativistic), electromagnetism and thermodynamics -, it is one of the mandatory theories studied at virtually all the intermediate-and advanced-level courses of physics around the world. As it normally happens with
Brazilian Journal of Physics. Publicado em: 2009-08
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19. Decomposition of stochastic flows / Decomposição de fluxos estocasticos
Este trabalho consiste basicamente em três níveis de decomposições de fluxos estocásticos: 1) decomposição via G-estruturas; 2) decomposição com componente em trajetórias hamiltonianas e 3) conjugações de fluxos aleatórios ...Observação: O resumo, na íntegra poderá ser visualizado no texto completo da tese digital
Publicado em: 2009
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20. Normal form in stability analysis of the L4 point of photogravitational problem / Formas normais no estudo da estabilidade para L4 no problema fotogravitacional
The study of the stability of L4 point of in the photogravitational problem is accomplished. Firstly a normalization algorithm for 2 and 3 degree freedom is accomplished. The equations of motion are written in an extended canonical and then, using the Hori-Lie, method put in a normal form. The stability of the system is analyzed by the theorem of Kovalev and
Publicado em: 2009
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21. Aspectos dinâmicos de espalhamento caótico clássico / Dynamical aspects of classical scattering
In this thesis we study different scattering systems with chaos. Chaotic scattering, present in a large variety of physical systems, is a type of transient chaos. While the phase-space of such systems is unbounded, irregular motion occurs only in a bounded area, called the scattering region. Still, any (nontrivial) scattering function relating initial condit
Publicado em: 2009
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22. Thermodynamic properties of the field electromagnetic field in the CPT-odd standard extended / Propriedades termodinâmicas do campo eletromagnético no setor CPT-ımpar do modelo padrão estendido
In this work we study the effects of the spontaneous breaking of Lorentz symmetry on black body radiation phenomenon in the context of the Maxwell-Caroll-Field-Jackiw (MCFJ) model. The MCFJ model is the electromagnetic CPT-odd sector of the standard model extension and, it presents for a purely space-like background a positive-definite hamiltonian. Firstly,
Publicado em: 2009
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23. Estudo das técnicas de obtenção de Hamiltonianos efetivos em Óptica Quântica
In the Quantum Optics area, the construction of effective hamiltonian is a matter of great importance, since from them we can generate and manipulate quantum states and logical operations. In this work we discuss 3 approximate methods for obtaining such effective hamiltonians: i) adiabatic elimination, ii) method of effective dynamics for oscillating hamilto
Publicado em: 2009
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24. Extended Bell´s Be-ables and Atenuattion × Amplification Competition. / Extensão dos Be-ables de Bell e Competição Atenuação x Amplificação
In the first part of this work we employ the Itô stochastic equation to extend Bells be-able interpretation of quantum mechanics to encompass dissipation, decoherence and quantum-to-classical transition through quantum trajectories. For a particular choice of the source of stochasticity, the one leading to a dissipative Lindblad type correction to the Hamil
Publicado em: 2009