https://repositorio.ufu.br/handle/123456789/20564 2026-04-26T11:43:11Z https://repositorio.ufu.br/handle/123456789/48605 Title: Eletrodinâmica Quântica de Cavidades na Faixa de Micro-ondas em Chips Semicondutores com Pontos Quânticos Definidos Eletrostaticamente Abstract: This work presents a theoretical and computational study of light-matter interaction in circuit quantum electrodynamics (cQED) architectures based on semiconductor quantum dots. Using the density matrix formalism and the theory of open quantum systems, we employ the Lindblad master equation to model dissipative mechanisms, including energy relaxation (T1) and decoherence (T2). The theoretical framework starts from the quantization of the electromagnetic field and the Jaynes-Cummings model within the rotating-wave approximation (RWA), and is extended to the dispersive regime via the Schrieffer-Wolff transformation, yielding effective Hamiltonians and dispersive shifts. We then perform numerical simulations to characterize coherent dynamics under microwave control and to compare the obtained results with experimental benchmarks reported in the literature, with emphasis on reproducing Rabi oscillations and Ramsey interferometry. Finally, we examine the limits of validity of the RWA at stronger coupling and demonstrate the controlled preparation of dark states (decoherence-free subspaces) in the two-qubit Tavis-Cummings model. 2026-02-28T00:00:00Z https://repositorio.ufu.br/handle/123456789/48360 Title: O Efeito Bumerangue Quântico 2024-04-26T00:00:00Z https://repositorio.ufu.br/handle/123456789/47784 Title: Modelos efetivos e fatores giromagnéticos via DFT2kp e funcionais híbridos Abstract: The Density Functional Theory (DFT) and the k · p method are two important techniques for calculating the electronic band structures of crystalline materials, which is fundamental for studying their electronic, optical, and transport properties. The DFT2kp package inte- grates DFT and the k·p method by implementing computational routines for the automatic construction of effective k · p models from ab initio data generated by DFT calculations. In this work, we investigated how the hybrid functional Heyd–Scuseria–Ernzerhof 2006 (HSE06) influences the values of the parameters (effective mass, g-factors, and Dresselhaus constant) extracted from effective k · p models for GaAs. To this end, DFT calculations were performed using both the semilocal Perdew–Burke–Ernzerhof Generalized Gradient Approximation (PBE-GGA) functional and the hybrid HSE06 functional in various config- urations. The results show that the HSE06 functional yields band gaps and k · p model parameters that are more accurate than those obtained with the semilocal functional. It was also observed that these parameters are sensitive to adjustments of the tunable HSE06 parameters. Finally, an analysis of the variation of the k · p parameters as a function of the band gap was carried out, demonstrating that applying a scissor-shift to PBE-GGA calculations can produce results similar to those obtained with HSE06, suggesting that in applications tolerating some inaccuracy, the high computational cost of HSE06 may not be justified. 2025-09-23T00:00:00Z https://repositorio.ufu.br/handle/123456789/46704 Title: Himália: Determinação da órbita do maior satélite irregular de Júpiter Abstract: This work presents a study focused on improving the orbital determination of Himália, the largest irregular satellite of Jupiter, through numerical integrations and statistical analysis of observational data collected between 1886 and 2022. The adopted approach initially considers equal weights for all observations, aiming to identify discrepancies and prepare the dataset for more refined future processing. The application of the initial part of this methodology resulted in a consistent preliminary orbit, with potential to enhance future predictions. The results demonstrate that careful selection and differentiated statistical treatment of the observations positively impact orbital accuracy, highlighting the effectiveness of the developed method. 2025-05-22T00:00:00Z