Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also in a digital version from UMI/Dissertation Abstracts International.

Thesis (PhD) - Swinburne University of Technology, Centre for Atom Optics and Ultrafast Spectroscopy, 2009. Thesis (PhD) - Australian Research Council, Centre of Excellence for Quantum-Atom Optics, 2009. / Thesis submitted for the degree of Doctor of Philosophy, Centre for Atom Optics and Ultrafast Spectroscopy, and, ARC Centre for Quantum-Atom Optics, Swinburne University of Technology, 2009. Typescript. Bibliography: p. 131-149.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 140-153). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Henry R. Glyde, Dept. Physics & Astronomy. Includes bibliographical references.

Thesis (Ph.D.)--Victoria University of Wellington, 2007. / "Version 1.1, 16 August 2007 (including corrections)" Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Conselho Nacional de Desenvolvimento Cientifico e Tecnológico / Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Nesta tese abordaremos os processos de fotoassociação em condensação de Bose- Einstein. Estes podem ser resumidos da seguinte forma: um condensado formados por átomos, inicialmente no estado fundamental, é iluminado com laseres de freqüência adequada, de tal modo que os átomos se combinem em moléculas. Tudo isto sem que o condensado deixe de existir por conta de instabilidades envolvidas neste processo. O que acabamos de descrever tem um equivalente na ótica quântica: a geração de segundo harmônico, cujas equações são semelhantes as do condensado. A natureza mais complexa das interações entre átomos, bem como a consideração de graus de liberdade internos, inclui efeitos potencialmente mais interessante que os encontrados com a luz. A quantidade de fenômenos que pode ser abordada é muito grande. As ressonâncias de Feshbach, por exemplo, são capazes de alterar a natureza da interação interatômica. Também podemos ter dois átomos fermiônicos formando uma molécula bosónica. Há efeitos de interferência entre dois condensados e estudos teóricos concernentes a fase relativa entre eles. Também é importante citarmos os estudo sobre vórtices e momento angular, enfim, há todo um zoológico de idéias a serem propostas teoricamente ou experimentalmente. Assim como em 1911 repentinamente surgiram novas áreas de estudo devido a descoberta da supercondutividade, aqui ocorre algo semelhante, uma fronteira da física foi aberta e devemos explora-la até que novos limites sejam alcançados.

In this thesis a number of aspects on possible manipulation of Bose-Einstein condensate in trapped atomic gases is investigated. First, a model for atom optical experiments involving Bose condensates is proposed and numerical simulations are presented to illustrate its characteristics. We demonstrate ways of focusing and splitting the condensate by modifying experimentally adjustable parameters. We show that there are at least two ways of implementing atom optical elements: one may modulate the interatomic scattering length in space, or alternatively, use a sinusoidal, externally applied potential. The temporal evolution of quasiparticle excitations is studied via the Gross-Pitaevskii Equation. Nonlinear mode mixing of quasiparticles is introduced, and is observed using a quasiparticle projection method. This is used as a basis of time-dependent finite temperature simulations, which we argue to be valid under regimes of high occupation number. An illustration via a closely related evaporative cooling simulation is provided. A phenomenological damping formalism for superfluidity near the λ point is adopted to describe the damping of excitations in a Bose-Einstein condensate. An estimate for the damping parameter is found. The damping formalism as a numerical tool to calculate the ground eigenstate of the condensate is explored. A novel, experimentally realisable interferometry for Bose-Einstein condensates using near-field diffraction is proposed. The scheme is based on the phenomenon of intermode traces or quantum carpets; we demonstrate the structured spatio-temporal pattern for the dilute, atomic Bose-Einstein condensate. The pattern is found to change with temperature, which allows us to perform interferometric temperature measurements. Finally, an output coupler for Bose-Einstein Condensates based on stimulated Raman transition is investigated. The spectrum and coherence are calculated for an atomic beam slowly coupled out of a trap containing a partially condensed Bose gas at finite temperatures. A number conserving Hartree-Fock-Bogliubov formalism has been used to incorporate finite temperature effects. Various different processes are found to become dominant for a suitable choice of the coupling parameters.

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