Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 176-190).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 250-257). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Carleton University, 1992. / Also available in electronic format on the Internet.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xiii, 131 p.; also includes graphics. Includes bibliographical references (p. 128-131). Available online via OhioLINK's ETD Center

Thesis (M.A.)--Ohio University, June, 2002. / Title from PDF t.p. Includes bibliographical references (leaves 223-228)

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Paul Eugenio, Florida State University, College of Arts and Sciences, Dept. of Physics. Title and description from dissertation home page (viewed June 8, 2006). Document formatted into pages; contains xix, 155 pages. Includes bibliographical references.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Física, Florianópolis, 2010 / Made available in DSpace on 2012-10-25T00:30:46Z (GMT). No. of bitstreams: 1 285471.pdf: 322523 bytes, checksum: 8f8b675363c4e1481e549c50d3bb5cec (MD5) / Investigamos a estrutura de estrelas híbridas levando em conta duas construções diferentes. Uma é baseada na condição de Gibbs para a coexistência de fases e considera a existência de uma fase mista para as densidades intermediárias, entre as densidades onde a matéria é composta por hádrons e as densidades onde a matéria é composta por quarks, a outra, é baseada na construção de Maxwell, e não possuí fase mista. Neste trabalho a fase de hádrons é descrita pelo modelo de Walecka não-linear (WNL) e a fase de quarks pelo modelo de Nambu-Jona-Lasinio (NJL). Concluímos que os resultados da matéria estelar macroscópica são dependentes do modelo, mas, não são significantemente diferentes para as duas construções.

Orientador: Lauro Tomio / Coorientador: Tobias Frederico / Banca: Vladimir Karmanov / Banca: Kazuo Tsushima / Banca: Alfredo Takashi Suzuki / Banca: Waynei Leonardo da Silva de Paula / Resumo: O trabalho apresentado nessa tese foi dedicado em explorar soluções de estado ligado para aequação de Bethe-Salpeter, obtidas diretamente no espaço de Minkowski. Para isso, consideramos um procedimento que combina a representação integral de Nakanishi para a amplitude Bethe-Salpeter, desenvolvido por N. Nakanishi na década de sessenta, em conjunto com a projeção da amplitude de Bethe-Salpeter no plano nulo, também conhecida como a projeção na frente de luz. Este método, além de permitir calcular as energias de ligação, que são acessíveis a partir de cálculos bem conhecidos no espaço Euclidiano, permite que se obtenha a amplitude Bethe-Salpeter no espaço de Minkowski e a função de onda de valência na frente de luz. A verificação da validade desse procedimento foi confirmada através de comparação da amplitude de Bethe-Salpeter obtida diretamente no espaço Euclidiano com a amplitude correspondente derivada da equação de Bethe-Salpeter, usando a representação integral de Nakanishi, uma vez a rotação de Wick é realizada. O sucesso dessa abordagem, quando aplicado ao problema do estado ligado de duas partículas escalares trocando uma outra partícula escalar no estado fundamental, assim como o estudo correspondente no limite de energia zero, nos motivou a ampliar a aplicação do procedimento para o estudo de outros problemas de interesse. Em particular, o método foi estendido para o estudo de sistemas com duas dimensões espaciais e uma temporal (2+1), considerando o interesse cresc... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The work presented in this thesis was dedicated in exploring bound-state solutions of the Bethe-Salpeter equation directly in the Minkowski space. For that, we consider a method that combines the Nakanishi integral representation for the Bethe-Salpeter amplitude, developed by Noboru Nakanishi in the sixties, together with the projection of the Bethe-Salpeter amplitude onto the null-plane, also known as the light-front projection. This approach, besides of allowing to compute the binding energies, which are accessible from the usual Euclidean calculation, enables to obtain the Bethe-Salpeter amplitude in the Minkowski space and the light-front wave function. The feasibility of such an approach is further verified by comparing the Bethe-Salpeter amplitude obtained directly in the Euclidean space with the corresponding amplitude obtained by solving the Bethe-Salpeter equation, using the Nakanishi integral representation, once the Wick rotation is performed to this latter. The success of the approach when applied to study the bound state problem of two-scalar particles exchanging another scalar particle in the ground state, as well as the corresponding study at the zero-energy limit, has encouraged us to extend this method to another interesting problems. In particular, we start by extending the method to study problems in (2+1) dimensions due to the increasing interest in the condensed-matter physics, like the study of Dirac electrons in graphene. In this initial examination we restrict to the scalar model, which enables us to access to the main difficulties that we will face when studying the fermion-fermion bound state problem. Hence, this calculation can be considered as the first step towards the implementation of the method to real fermionic problems. The previous calculations have been performed by considering the ladder approximation for the... (Complete abstract click electronic access below) / Doutor

Includes bibliographical references. / Various calculations· of the evolution of the hadron gas in the early universe are carried out. To determine the starting point for the evolution equations a phase transition between the quark-gluon plasma phase and the hadron gas phase is constructed. A simple calculation leads to an estimate of the chemical potential of baryons at the quark-hadron phase transition in the early universe. We investigate how the transition temperature depends on the equations of state for the bagged quark and the hadron phase. A particle density evolution model is introduced which predicts the temperature at which particle species drop out of equilibrium (freeze-out) in an expanding universe. We then construct dynamical evolution equations to describe the reactions of interacting pions and photons. In order to model a more realistic hadron gas, we include kaons and finally nucleons and hyperons into the model universe. The results indicate that this type of model should be extended to include more interacting particle species and that a more realistic evolution model is dependent on obtaining accurate reaction cross-sections.

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