Termalização e correlações quânticas nos contextos de sistemas quânticos abertos e cadeias de spins

• Ano de defesa: 2013
• Autor(a) principal: Oliveira, Thiago Werlang de
• Orientador(a): Villas-Bôas, Celso Jorge
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• País: BR
• Palavras-chave em Português: Física; Transição de fase quântica; Decoerência (Decoherence); Emaranhamento; Correlações Quânticas; Sistemas Quânticos Abertos; Termalização
• Palavras-chave em Inglês: Quantum Correlations; Open Quantum Systems; Quantum Phase Transitions; Thermalization
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://repositorio.ufscar.br/handle/ufscar/4950

In this thesis, we study the behavior of Quantum Discord in the contexts of open quantum systems and spin chains. Furthermore, we investigate the thermalization process of a spin chain due to interaction with the environment. First, we present a review on the concept of quantum correlation, beginning with the first ideas on non-locality, and leading to the measure of quantum correlations called Quantum Discord. Afterwards, we study the dynamics of the quantum correlations between two non-interacting qubits coupled to Markovian and non- Markovian thermal reservoirs. In the context of spin chains, we investigate the behavior of quantum correlations at finite temperatures, starting with a system composed of two interacting spins, described by XYZ model, in order to generalize this study to the case of infinite unidimensional spin chains, described by XY and XXZ models. In this context, we investigate the relationship between quantum correlations and quantum phase transitions present in these two models. We conclude this thesis with a study of the thermalization process of two interacting spins weakly coupled to independent bosonic thermal reservoirs, or to a single collective reservoir, besides presenting some results for larger systems, composed of an arbitrary number of spins.