Ações efetivas para teorias de Gauge: campo eletromagnético e o campo de Kalb-Ramond

• Ano de defesa: 2018
• Autor(a) principal: Costa, Rafael Luis Junqueira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Lavras; Programa de Pós-graduação em Física; UFLA; brasil; Departamento de Física
• Palavras-chave em Português: Ação efetiva (AE); Ação efetiva em 1-loop; Criação de pares; Campo de Kalb-Ramond; Teoria quântica de campos; Effective action; 1-loop effective action; Pair creation; Kalb-Ramond field; Quantum field theory; One-loop effective action; Teoria Geral de Partículas e Campos
• Link de acesso: http://repositorio.ufla.br/jspui/handle/1/31548

The present dissertation presents the calculation of effective 1-loop actions for gauge theories such as the electromagnetic field and the Kalb-Ramond field. Effective actions work as quantum corrections to classical theories in order to explain certain quantum phenomena. For example, in electromagnetism, the nonlinear effects as the singularity of the self-energy of a point charge and the polarization of the vacuum. On the polarization of the vacuum the Euler-Heisenberg Lagrangian is highlighted. Thus, this work will present a method of calculation of the same denominated method of proper time, proposed by Schwinger. The analysis will follow the formalism of Path Integrals, thus allowing a very clear discussion. An analysis of the creation of electron-positron pairs in vacuum due to an external electromagnetic field will also be made. As well as, some applications of effective actions, such as the Casimir effect and the effective action at the finite temperature. In addition, the effective action for three-dimensional QED will also be calculated. And last the effective action for the Kalb-Ramond field will be calculated.