Bethe Ansatz
Mostrando 13-19 de 19 artigos, teses e dissertações.
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13. Metodos analiticos em sistemas fortemente correlacionados unidimensionais : um estudo da rede de Kondo por bosonização e da cadeia de Heisenberg pelo anstaz de Bethe
In this thesis, we studied the one-dimensional Kondo lattice model with abelian bosonization and the Heisenberg chain with the Bethe ansatz. We connected the Kondo lattice with the cooperative Jahn-Teller and with the 2 Luttinger liquids interacting by hopping. The main technique used was the renormalization group for the generalized Coulomb gas, that is obt
Publicado em: 2001
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14. Processos estocásticos de reação e difusão na rede e cadeias quânticas
Neste trabalho investigamos alguns processos estocásticos de reação e difusão na rede. Em particular, determinamos as classes de universalidade de comportamento Crıtico de um processo de crescimento de superfıcies fora do equilıbrio e do processo de contato básico. Para isso utilizamos técnicas de diagonalizacao numérica exata e idéias
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/06/2000
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15. Exact solution of asymmetric diffusion with N classes of particles of arbitrary size and hierarchical order
The exact solution of the asymmetric exclusion problem with N distinct classes of particles (c = 1, 2, ..., N), with hierarchical order is presented. In this model the particles (size 1) are located at lattice points, and diffuse with equal asymmetric rates, but particles in a class c do not distinguish those in the classes c' > c from holes (empty sites). W
Brazilian Journal of Physics. Publicado em: 2000-12
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16. Exact solution of asymmetric diffusion with second-class particles of arbitrary size
The exact solution of the asymmetric exclusion problem with first- and scond-class particles is presented. In this model the particles (size 1) of both classes are located at lattice points, and diffuse with equal asymmetric rates, but particles in the first class do not distinguish those in the second class from holes (empty sites). We generalize and solve
Brazilian Journal of Physics. Publicado em: 2000-03
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17. Efeitos de tamanho na cadeia de Heisenberg-Ising via Ansatz de Bethe
Neste trabalho, estudamos os efeitos de tamanho no hamiltoniano de Heisenberg-Ising na fase não crítica. Para tanto, utilizamos o ansatz de Bethe para resolver cadeias de spins com até mil sítios. Estudamos o comportamento, com o tamanho da cadeia, do estado fundamental antiferromagnético, do estado do gap de massa e do estado da onda de spin antiferrom
Publicado em: 1997
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18. Numerical Renormalization-group Computation of Specific Heats. / Calor específico do modelo de Anderson de uma impureza por grupo de renormalização numérico
The specific heat and the entropy of the one-impurity symmetric Anderson Model are calculated using the Numerical Renormalization Group (NRG). The heart of the method is the logarithmic discretization of the metal conduction band where the impurity is coupled. However, this discretization, inherent in the method, introduces oscillations in the thermodynamica
Publicado em: 1995
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19. Efeitos de tamanho em cadeias de Heisenberg-ising com interações antiferromagneticas
Finite Heisenberg-Ising quantum chains, for spin s = 1/2 and periodic boundary conditions, are exactly solved by numerical methods diagonalizing the Hamiltonian using the Lanczos method up to size N = 28 spins. Interesting physical quantities are computed, including the ground state energy, the mass gap, the spin-wave velocity, and correlation functions. Sca
Publicado em: 1991