Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-09-27T14:51:52Z No. of bitstreams: 2 Tese - Arthur Bartholo Gomes - 2018.pdf: 2713087 bytes, checksum: 1ea8f8d17d2c744c5d430838baafccd4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-09-28T14:11:13Z (GMT) No. of bitstreams: 2 Tese - Arthur Bartholo Gomes - 2018.pdf: 2713087 bytes, checksum: 1ea8f8d17d2c744c5d430838baafccd4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-09-28T14:11:13Z (GMT). No. of bitstreams: 2 Tese - Arthur Bartholo Gomes - 2018.pdf: 2713087 bytes, checksum: 1ea8f8d17d2c744c5d430838baafccd4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-08-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This thesis aims to clarify the meaning of the concept of double reflection in Kierkegaard, by elaborating reflexivity in kierkegaardian philosophy and by a retrospective tracing of how this concept can be found and formulated in Fichte and in early German romanticism. The idea of a reflection on reflection, which Kierkegaard identifies with the double reflection in his work and which is used as an operative concept to explain his philosophical, literary and religious authorship, was first formulated in Fichte's critical philosophy, and from then on it was submitted to a metacritical interpretation in the Frühromantik, which directly influenced Kierkegaard's appropriation. In order to lay the foundations for an understanding of the concept of double reflection, the work should cover not only the delineation of the concept of reflection by itself in each of these authors, but also in parallel to relate it with the conception of a reflective consciousness or individuality in each author. Although it is possible to trace this sequential line formed by this concept in these three authors, the specific differences it acquires in each of them compels the confrontation with both romanticism and idealism in Kierkegaard's work, with which he seeks to dialogue in order to delimit his religious philosophy. / Esta tese pretende esclarecer o significado do conceito de dupla reflexão em Kierkegaard, a partir de uma elaboração da reflexividade na filosofia kierkegaardiana e de um traçamento retrospectivo da forma como este conceito pode ser encontrado e formulado em Fichte e no primeiro romantismo alemão. A ideia de uma reflexão da reflexão, que Kierkegaard identifica com a dupla reflexão em sua obra e dela se utiliza como conceito operativo para explicar sua autoria filosófica, literária e religiosa, foi formulada primeiramente na filosofia crítica de Fichte, e a partir daí sofreu uma interpretação metacrítica nos Frühromantik, que influenciou diretamente a apropriação de Kierkegaard. Para lançar as bases para a compreensão do conceito de dupla reflexão, o trabalho deverá percorrer não somente o delineamento do conceito reflexão por si mesmo em cada um destes autores, mas também relacioná-lo paralelamente com a concepção que cada um deles tem da ideia de uma consciência ou individualidade reflexiva. Embora seja possível traçar esta linha sequencial formada por este conceito nestes três autores, as diferenças específicas que ele adquire em cada um deles compele à confrontação tanto com o romantismo quanto com o idealismo na obra de Kierkegaard, com os quais ele busca dialogar para delimitar sua filosofia religiosa.

Atom interferometers and gyroscopes are highly sensitive atom-optical devices which are capable to measure inertial, gravitational, electric, and magnetic fields and to sense rotations. Theoretically, the signal-to-noise ratio of atomic gyroscopes is about a hundred billion times more than that of their optical counterparts for the same particle flux and the enclosed area. Ultra cold atoms from a Bose-Einstein condensate (BEC) can easily be controlled and coherently manipulated on small chips by laser pulses. Atom-optical devices will therefore play a significant role in fundamental research, precision measurements, and navigation systems. In BEC-based atom interferometers, a BEC in a trap is split by using laser pulses, the split clouds are allowed to evolve, they are reflected, and then recombined by laser pulses to observe interference. The split clouds accumulate spatial phase because of the trap and the nonlinearity caused by atom-atom interactions. A velocity mismatch due to reflection laser pulses also introduces a phase gradient across each cloud. These factors contribute to spatial relative phase between the clouds at recombination, causing the loss of contrast of the interference fringes. The main objective of this dissertation is to study the dynamics of a split condensate in atom Michelson interferometers, investigate the effect of trap frequencies, nonlinearity, and the velocity mismatch on the contrast, and to obtain the best theoretical limit of performance in terms of the experimental parameters: trap frequencies, number of atoms, and the velocity imparted to the clouds by the splitting laser pulses.