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Itens para a visualização no momento 101-110 of 240
Transição de fase quântica e modelos de spins frustrados
(Universidade Federal de São Carlos, 2007-03-15)
In this thesis, we will study the quantum phase transition of frustrated quantum spin
models: (i) van Hemmen model ( S = 1) with transverse and anisotropic biaxial field (ii)
Heisenberg model (S = 1/2 ) with competitive ...
Dopagem substitucional de peroviskitas com metais de transição 3d: um estudo ab initio
(Universidade Federal de São Carlos, 2022-10-04)
The global demand for energy has brought into focus the halide perovskites as materials
with high potential for applications in photovoltaic devices. Great progress has been made
in the last 10 years, demonstrating the ...
Propriedades magnéticas de BiMn2O5 e Fe3O2BO3
(Universidade Federal de São Carlos, 2018-02-26)
In this work, an exploration of the synthesis and magnetoelectric properties of single-crystals of BiMn2O5 and a systematic study of the magnetic properties of Fe3O2BO3 are presented. Despite the unlike composition, both ...
Turbulência de Ondas em condensados de Bose-Einstein
(Universidade Federal de São Carlos, 2018-02-19)
In this work we used as a starting point the theory developed by Zakharov and Nazarenko for treating wave turbulence in systems
with weak non linearity such as atomic Bose-Einstein condensates with low enough temperature ...
Resposta óptica de sistemas atômicos no espaço livre ou aprisionados dentro de cavidades ópticas no regime de armadilhamento coerente de populações
(Universidade Federal de São Carlos, 2018-02-28)
The aim of this work is to study the electromagnetically induced transparency (EIT) and
the coherent population trapping (CPT) phenomena in three-level systems, such as atoms
and quantum dot molecules (QDM). The present ...
Técnicas de difração de elétrons e de caracterizações elétricas e térmicas combinadas para análise de transformações de simetria em estruturas perovskitas distorcidas : caso das soluções sólidas (Pb1-xCax)TiO3
(Universidade Federal de São Carlos, 2017-03-03)
The main objective of this work was the unequivocally determination of the crystal symmetry
of distorted perovskite structure by direct and indirect methods, with the solid solution system
Pb1-xCaxTiO3 (PCT) as the case ...
Estudos sobre a inclusão da correlação eletrônica do alvo no espalhamento elástico elétron-molécula e sobre a ionização molecular por impacto de elétrons
(Universidade Federal de São Carlos, 2003-12-10)
In this work we present two contributions to the electron-molecule collision theory. Firstly, we present a new theoretical procedure to introduce the target electronic correlation in the elastic electron-molecule scattering. ...
Emaranhamento intrínseco em sistemas tipo-Dirac
(Universidade Federal de São Carlos, 2018-03-06)
Dirac equation is supported by a $SU(2) \otimes SU(2)$ group structure, such that its solutions describe two discrete degrees of freedom, intrinsic parity and spin, which in general are entangled. In this work we will ...
Termodinâmica de buracos negros de Schwarzschild
(Universidade Federal de São Carlos, 2018-05-28)
This dissertation consists of a review about some aspects of Schwarzschild black hole thermodynamics and includes a discussion related to the temporal evolution of the masses of these black holes in a thermodynamic context. ...
Estudos de vidros fluoroboratos e fluorogermanatos de chumbo, através de técnicas de espectroscopia óptica e de ressonância magnética
(Universidade Federal de São Carlos, 2018-12-04)
In this work two studies on rare earth−doped (Eu3+, Yb3+) lead fluorogermanate (GeO2−PbO−PbF2) and fluoroborate glasses (B2O3 −PbO −PbF2) were investigated. The main advantages of these glasses are their chemical stability ...