Efeitos coerentes em pontos quânticos semicondutores

• Ano de defesa: 2019
• Autor(a) principal: Silva, Vanbasten Fernandes
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Uberlândia; Brasil; Programa de Pós-graduação em Física
• Palavras-chave em Português: Pontos quânticos; Transparência eletromagneticamente induzida; Fase geométrica; Fotocélulas; Pulsos gaussianos; Quantum dots; Electromagnetically induced transparency; Geometric phase; Photocells; Gaussian pulses; Física; Células fotoelétricas; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA DA MATERIA CONDENSADA::PROP.OTICAS E ESPECTROSC.DA MAT.CONDENSOUTRAS INTER.DA MAT.COM RAD.E PART.
• Link de acesso: https://repositorio.ufu.br/handle/123456789/24609; http://dx.doi.org/10.14393/ufu.te.2019.318

In the present work we investigated the physical properties of quantum systems of two [1], three [2] and four [3] levels formed by electrons, excitons and trions using the formalism of the density matrix. The unitary evolution of the systems is based on the Liouville-von Neumann [4] master equation and the decoherence e ects are included according to the Lindblad [5] formalism. We investigated the optical properties [6] of these systems, looking for favorable conditions to the regime of electromagnetically induced transparency [7]. We calculate the geometric phases associated with the two and three level systems for pure and mixed states according to the formalism de ned by Pancharatnan [8]. In the four-level system we manipulate Gaussian pulses of test and control, provoking temporal delays [9], chirps [10] and creating ultra-short pulse trains [11] to induce coherent population accumulation and investigate the soliton propagation of light in the regime of transparency associated with the quantum memory phenomenon. We investigated the e ciency of a photocell of quantum dots coupled by tunnels in the presence of an external source of radiation within the Markovian [12] approximation for the interaction between system and reservoir.