Optimization and application of the quantum adiabatic theorem, and the quantum origin of classical interference

• Ano de defesa: 2022
• Autor(a) principal: Souza, Paulo José Paulino de
• Orientador(a): Villas-Bôas, Celso Jorge
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de São Carlos; Câmpus São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• Palavras-chave em Português: Teorema adiabático quântico; Braquistócrona adiabática quântica; Busca adiabática quântica; Baterias quânticas supercondutoras; Recozimento quântico; Interferência quântica
• Palavras-chave em Inglês: Quantum adiabatic theorem; Quantum adiabatic brachistochrone; Quantum adiabatic search; Superconducting quantum batteries; Quantum annealing; Quantum interference
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA::FISICA GERAL::FISICA CLASSICA E FISICA QUANTICA; MECANICA E CAMPOS
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/16149

In this master’s thesis, we developed three different topics. In the first topic, we studied the quantum adiabatic brachistochrone method (QAB) for optimizing adiabatic dynamics. In the first part of this study, we reported the investigation of the charging and discharging processes of a transmon superconducting three-level quantum battery. The charging process was enhanced using the QAB method, in which we analyzed the effect of constraining the interpolation functions. We completed the battery study by showing that its self-discharging process, which is how the device loses its charge to the environment, is non- Ohmic. Furthermore, we considered the application of the QAB method to the adiabatic Grover algorithm for times when there are limited resources for its execution, for instance when there is a limit on the maximum power of the external fields or in the available total energy. The second part is concerned with the theory of the D-Wave’s quantum annealer and its limitations, as the lack of global connections between the qubits. For evaluating the state-of-the-art of this quantum simulator, we solved the traveling salesman problem on it. Moreover, we did a literature review about problems this processor can handle and different strategies to avoid its limitations. Finally, in the third topic, we proved that describing light-matter interaction using quantum fluctuations yields ambiguities for multi-modes of light. We showed that classical interference emerges in quantum optics due to collective bright and dark states of light. In a multi-mode case, the criterion for a ground-state atom to be excited is the existence of a projection on non-dark states rather than quantum fluctuations.