Now showing items 1-10 of 70
Formulação canônica no plano nulo
(2009) [Tese de doutorado]
Mistura de sabor e violação de CP
(2007-03-30) [Tese de doutorado]
he aim of this thesis is the study of the properties of CP violation and flavor mixing in the Standard Model (SM) and in some of its extensions. We study the connection between both phenomena and their relation with the ...
Modelo de Fisher-Kolmogorov em dinâmica populacional com capacidade de suporte espacialmente dependente
(2003-03-18) [Tese de doutorado]
We study the spatial and temporal dynamics of a biological population by means of the Fisher-Kolmogorov equation, taking into account a logistic growth and a fickian diffusion. Special attention is payed to the case where ...
Quebra de Simetria no Universo Primordial
(2007-04-27) [Tese de doutorado]
Analytic expressions for solutions in the Standard Model are presented here for all combinations of 'lâmbda' = 0, 'lâmbda'diferente 0, 'capa' = 0 and 'capa'diferente'0 in the presence and absence of radiation and nonrelativistic ...
Compactificação alternativa de dimensões extras em gravitação de Brans-Dicke
(2009-09-08) [Tese de doutorado]
After a brief introduction of some gravitational aspects of the Randall-Sundrum braneworld model as well as of the Brans-Dicke (BD) gravity, we propose two braneworld models using the, local and global, cosmic strings in ...
Uma abordagem de potencial e massa efetiva e a descrição de espaço de fase quântico para tratar sistemas de spins: Caracterizando o tunelamento de spin e propriedades da molécula de Fe8
(2009-03-27) [Tese de doutorado]
We have used an angle-based description and the quantum discrete phase space formalism to characterize Fe8 cluster properties. Through the angle-based approach we have calculated the the ground state barrier height, the ...
Aspectos clássicos de teorias de segunda ordem
(2009-06-15) [Tese de doutorado]
In this work, classical and semiclassical aspects of second order theories were analyzed. First the formulation of a gauge theory for systems whose Lagrangian for the gauge field depends on the field itself and its first ...
Cordas cósmicas e gravitação planar de ordem superior
(2008-02-29) [Tese de doutorado]
The possibility of generalizing gravity in 2+1 dimensions to include higher-derivative terms, thereby allowing for a dynamical theory, opens up a variety of new interesting questions. This is in great contrast with pure ...
Alguns problemas da radiação síncrotron
(2002) [Tese de doutorado]
Pure spinor superstring partition function
(2008-12-12) [Tese de doutorado]
In this thesis, we have calculated the partition function of pure spinors. The computation is performed by using two different methods, namely ghosts-for-ghosts (up to the twelth mass-level) and fixed point (up to the fifth ...