Path Integrals
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Simulações Monte Carlo de integrais de trajetória : propriedades elásticas do 4He sólido / Path integrals Monte Carlo simulations : elastic properties of 4He
The path-integral Monte Carlo (PIMC) method is a sophisticated approach for the simulation of many-body quantum systems. In particular, it has been extensively used for the study of manybody bosonic systems such as 4He. The main objective of the present dissertation is to apply the PIMC method to determine the elastic constants of solid 4He in its hcp phase.
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/11/2010
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2. Teoria de rough paths via integração algebrica / Rough paths theory via algebraic integration
Introduzimos a teoria dos p-rough paths seguindo a abordagem de M. Gubinelli, conhecida por integração algébrica. Durante toda a dissertação nos restringimos ao caso 1
Publicado em: 2009
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3. Processos estocásticos em física: teoria e fundamentos
This work discusses some problems in physics using the language of stochastic processes. Firstly, we discuss the relationships between the formalisms of master equations, path integrals, and jumping processes. Each of them is a different prescription to define a Markovian process. Using these formalisms, we discuss the applicability of the classic Langevin m
Publicado em: 2009
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4. 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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5. On the quantum dynamics of non-commutative systems
This is a review paper concerned with the global consistency of the quantum dynamics of non-commutative systems. Our point of departure is the theory of constrained systems, since it provides a unified description of the classical and quantum dynamics for the models under investigation. We then elaborate on recently reported results concerned with the suffic
Brazilian Journal of Physics. Publicado em: 2008-06
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6. Integrals in the coherent state representation / Integrais de trajetoria na representação de estados coerentes
The overcompleteness of the coherent states basis gives rise to a multiplicity of representations of Feynman?s path integral. These different representations, although equivalent quantum mechanically, lead to different semiclassical limits. Baranger et al derived the semiclassical limit of two path integral forms suggested by Klauder and Skagerstam. Each of
Publicado em: 2008
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7. Métodos numéricos euleriano-lagrangeanos para leis de conservação / Eulerian-lagrangina numeric methods for conservation laws
Este trabalho apresenta uma família de novos métodos numéricos euleriano-lagrangeanos localmente conservativos para leis de conservação hiperbólicas escalares. Estes métodos não utilizam soluções analíticas de problemas de Riemann e são bastante precisos na captura de saltos nas soluções. Estes métodos foram introduzidos, implementados computa
Publicado em: 2008
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8. Path integrals and perturbation theory for stochastic processes
We review and extend the formalism introduced by Peliti, that maps a Markov process to a path-integral representation. After developing the mapping, we apply it to some illustrative examples: the simple decay process, the birth-and-death process, and the Malthus-Verhulst process. In the first two cases we show how to obtain the exact probability generating f
Brazilian Journal of Physics. Publicado em: 2003-03
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9. Integrais de caminho para o mapa do padeiro
We derive a formally exact sum of path integrals for the quantum propagator of the baker s transformation. The phases depend only on the classical actions as in usual phase space path integrals and the sums are over alI the symbolic orbits. The deduction depends on multiple Poisson transformations, which lead to a further infinite sum of integrals, but our c
Publicado em: 1995
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10. Influencia do campo de radiação no processo de interferencia eletronica
We develop a non-relativistic quantum formulation for the dynamics of na electron taking into account the effects of the coupling to its own radiation field, which give rise to radiation damping. For this purpose we have applied the Feynman-Vernon approach, obtaining the reduced density operation of the electron via path integrals. In the classical limit, so
Publicado em: 1989
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11. Automatic classification of protein structure by using Gauss integrals
We introduce a method of looking at, analyzing, and comparing protein structures. The topology of a protein is captured by 30 numbers inspired by Vassiliev knot invariants. To illustrate the simplicity and power of this topological approach, we construct a measure (scaled Gauss metric, SGM) of similarity of protein shapes. Under this metric, protein chains n
The National Academy of Sciences.