Quantum work-like functional under the Keldysh contour approach

• Ano de defesa: 2024
• Autor(a) principal: Afonso, Ricardo José da Silva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Integral de trajetória; Path integral; Quantum work; Simetria; Symmetry; Termodinâmica; Thermodynamics; Trabalho quântico
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/76/76131/tde-14012025-121432/

This thesis explores the concept of quantum work within the framework of the Keldysh contour approach, a technique rooted in the non-equilibrium dynamics of quantum systems. The work begins with a review of classical fluctuation relations and their quantum counterparts, emphasizing the challenges in defining work in quantum systems due to the lack of a unique trajectory in phase space. Utilizing the two-point measurement protocol, we derive the characteristic function of quantum work and discuss its implications for the symmetry properties in quantum thermodynamics. A key contribution of this thesis is the formulation of a path-integral representation for quantum work, leading to the identification of a work-like functional. This functional is shown to be directly related to the breaking of symmetry in out-of-equilibrium dynamics. The results presented extend the applicability of fluctuation theorems and offer new insights into the role of symmetry in quantum thermodynamic processes.