https://repositorio.ufpb.br/jspui/handle/123456789/4 2026-07-24T09:35:14Z 2026-07-24T09:35:14Z Santana, Maria Isabel Ramos https://repositorio.ufpb.br/jspui/handle/123456789/38438 2026-07-23T06:13:11Z 2025-09-30T00:00:00Z

Título: Montagem de um sistema de microscopia holográfica digital Autor(es): Santana, Maria Isabel Ramos Orientador: López, Jesús Pavón Abstract: Digital Holographic Microscopy (DHM) is a powerful interferometric technique that enables high-resolution, label-free, three-dimensional reconstruction of microscopic phase objects. This project aims to develop a robust DHM system based on a Mach-Zehnder interferometer architecture, precisely aligned on an inertial table to ensure phase stability. The system is designed for the acquisition and numerical reconstruction of digital holograms, providing quantitative phase contrast imaging. We present a comprehensive theoretical and practical framework for the system’s assembly, alongside a detailed analysis of the numerical methods employed for holographic reconstruction. The capabilities of our apparatus are demonstrated through the imaging of human red blood cells, highlighting its potential for medical diagnostics—particularly in identifying morphological abnormalities associated with conditions such as sickle cell anemia. Our results underscore the viability of DHM as a powerful tool for non-invasive biological analysis and pave the way for future integration with automated disease screening protocols. Editor: Universidade Federal da Paraíba Tipo: TCC

2025-09-30T00:00:00Z Vasconcelos, Hugo Rodrigues https://repositorio.ufpb.br/jspui/handle/123456789/38402 2026-07-21T06:16:02Z 2025-10-03T00:00:00Z

Título: O papel das condições de fronteira na energia de vácuo: uma análise via métodos global e local Autor(es): Vasconcelos, Hugo Rodrigues Orientador: Mota, Herondy Francisco de Santana Abstract: This work investigates the Casimir effect for a real scalar field in (3+1) dimensions, considering different boundary conditions - Dirichlet, Neumann, mixed, and quasi-periodic. Two distinct methodologies for calculating the vacuum energy are analyzed: the global approach, based on the sum over the field modes, and the local approach, founded on the expectation value of the energy-momentum tensor. We demonstrate that, in the case of infinite parallel plates, the two approaches are not equivalent due to the non-commutativity between the mode summation and spatial integration. In this scenario, the energy obtained by the local method exhibits divergences near the surfaces, while the global approach, after zeta function regularization and subsequent renormalization, yields finite results consistent with the literature. In contrast, for the quasi-periodic case where there are no physical boundaries, the two methodologies coincide exactly, indicating that the discrepancy stems from the translational symmetry breaking caused by the boundary conditions. Using the Wightman function and the energy-momentum tensor formalism, we derive unified expressions that describe both scenarios. For the massive case, we demonstrate the exponential decay of the vacuum energy in the large-mass limit, also recovering known results for the massless field. The Casimir force per unit area is calculated for all configurations, showing attractive or repulsive behavior depending on the boundary conditions and the phase parameter in the quasi-periodic case. The results underscore the relevance of boundary conditions in determining the vacuum energy and suggest directions for future extensions, such as the analysis of other quantum fields (electromagnetic and fermionic), the inclusion of thermal effects, the study of non- trivial geometries and topologies, and also investigations into non-minimal coupling with curvature. This work contributes to the fundamental understanding of quantum vacuum properties in confined and compactified spaces, establishing connections between global and local formalisms in quantum field theory calculations. Editor: Universidade Federal da Paraíba Tipo: TCC

2025-10-03T00:00:00Z Sampaio, Kelvin Costa Rocha https://repositorio.ufpb.br/jspui/handle/123456789/37882 2026-03-24T06:03:48Z 2025-10-03T00:00:00Z

Título: Gravidade quântica a baixas energias: correções fenomenológicas da mecânica quântica Autor(es): Sampaio, Kelvin Costa Rocha Orientador: Lobo, Iarley Pereira Abstract: This study aims to explore how quantum systems and decoherence characteristics impact the field of quantum gravity, highlighting the importance of phenomenological models that bridge microscopic-scale effects with observable observations. The research includes a review of the theoretical principles of quantum mechanics and relativity, emphasizing suggestions for systematic and stochastic modifications in kinematics inspired by quantum gravity scenarios. Furthermore, the observational consequences and limitations of the models in question are highlighted, connecting the formulated theory to possible effects that can be detected at accessible energies. The findings suggest that, although quantum gravity remains an open challenge, phenomenological analyses may offer interesting clues for future investigations and experiments. Editor: Universidade Federal da Paraíba Tipo: TCC

2025-10-03T00:00:00Z Guinote, Bárbara Vitória Silva https://repositorio.ufpb.br/jspui/handle/123456789/34796 2025-06-11T06:13:39Z 2025-05-05T00:00:00Z

Título: Um estudo da eletrodinâmica acoplada a férmions e alguns aspectos da mecânica quântica relativística Autor(es): Guinote, Bárbara Vitória Silva Orientador: Porfírio, Paulo José Ferreira da Silva Abstract: This work seeks to explore the foundations of Classical and Quantum Field Theory, establishing a bridge between Classical Mechanics and modern concepts such as symmetry and gauge invariance. It begins by developing the variational and tensorial formalism required to understand the transition from classical physics to field formulations. Then, electromagnetism is examined from the perspective of a gauge theory, with emphasis on the covariance of Maxwell’s equations and the distinction between global and local symmetries. The study also addresses the gauge principle and its role in quantum mechanics. Finally, relativistic quantum mechanics is introduced through the Klein-Gordon and Dirac equations, discussing their solutions, probability currents, and the famous Dirac Sea interpretation. This study aims to provide a solid conceptual and mathematical foundation for understanding the fundamental theories governing physical interactions in various regimes. Editor: Universidade Federal da Paraíba Tipo: TCC

2025-05-05T00:00:00Z