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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

A QUEST for BEC : an all optical alternative

Barrett, Murray Douglas 05 1900 (has links)
No description available.
102

Dynamics of Bose-Einstein Condensates in Josephson Junctions

Semple, Jaclyn 11 January 2011 (has links)
We numerically solve the Gross-Pitaevskii equation and the Bogoliubov de Gennes equations for a double well potential in order to model the dynamics of a Bose-Einstein condensate in a Josephson junction. First, the two dynamical regimes of the Josephson junction, that is, Josephson oscillations and self-trapping, are investigated under the application of a large sudden perturbation. It is found that the Josephson dynamics have a strong dependence on the strength of the interatomic interaction, and we observe the breakdown of the two-mode approximation. Second, we study the control of the dynamics through the use of a time-dependent, tilted double well potential. In the context of complete population transfer, the effect of the interactions on the adiabaticity and self-trapping is discussed in terms of a Landau-Zener-like model. We then explore the splitting of the condensate and the resulting dynamical behaviour by keeping the interaction strength constant, but changing the rate of the tilt sweep. Lastly, we examine the effect of the tilt sweep rate on the dynamics of population transfer. We observe a dependence of the self-trapping on the adiabaticity. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2011-01-10 16:31:43.127
103

Bose-Einstein Condensate Wavefunction Reconstruction Through Collisions with Optical Potentials

Ellenor, Christopher William 30 August 2011 (has links)
A new technique for the interferometric measurement of an atomic wavefunction is introduced theoretically, which is able to extract phase and amplitude information in a single measurement. I focus on the application of this technique to the single-particle wavefunction of a Bose condensed cloud of rubidium atoms. The technique differs from existing techniques mainly in its simplicity, as it requires only a single laser beam to be added to a typical Bose-Einstein condensation apparatus. A second novel aspect is the consideration of condensate collisions with an optical potential in the low-intensity limit where the potential barrier may be viewed as a phase mask. The technique is then demonstrated experimentally. A related effect, the transient enhancement of momentum during a collision, first predicted by JG Muga et al., has also been demonstrated. Finally, significant redesign and construction of an apparatus to produce condensates of 87Rb is documented. The main result of this work is the production of pure condensates of up to 150k atoms which can be repeated every 45s. A calibration technique is devised and demonstrated, whereby copies of the condensate are made, and the copies are used to reduce the centre-of-mass momentum uncertainty of the interacting cloud by a factor of five.
104

Bose-Einstein Condensate Wavefunction Reconstruction Through Collisions with Optical Potentials

Ellenor, Christopher William 30 August 2011 (has links)
A new technique for the interferometric measurement of an atomic wavefunction is introduced theoretically, which is able to extract phase and amplitude information in a single measurement. I focus on the application of this technique to the single-particle wavefunction of a Bose condensed cloud of rubidium atoms. The technique differs from existing techniques mainly in its simplicity, as it requires only a single laser beam to be added to a typical Bose-Einstein condensation apparatus. A second novel aspect is the consideration of condensate collisions with an optical potential in the low-intensity limit where the potential barrier may be viewed as a phase mask. The technique is then demonstrated experimentally. A related effect, the transient enhancement of momentum during a collision, first predicted by JG Muga et al., has also been demonstrated. Finally, significant redesign and construction of an apparatus to produce condensates of 87Rb is documented. The main result of this work is the production of pure condensates of up to 150k atoms which can be repeated every 45s. A calibration technique is devised and demonstrated, whereby copies of the condensate are made, and the copies are used to reduce the centre-of-mass momentum uncertainty of the interacting cloud by a factor of five.
105

Quantum evaporation from superfluid helium

Matthias, John Robert January 1998 (has links)
No description available.
106

Collective and collisional properties of the Rubidium quantum gas

Buggle, Christian, January 2005 (has links)
Proefschrift Universiteit van Amsterdam. / Met bibliogr., lit. opg. - Met samenvatting in het Nederlands en Duits.
107

The stability of a continuously pumped atom laser

Haine, Simon A. January 2002 (has links)
Thesis (BSc. (Hons))--Australian National University, 2002. / Available via the Australian National University Library Electronic Pre and Post Print Repository. Title from title screen (viewed Feb. 18, 2003). "A thesis submitted as partial fulfillment of the requirements for the degree of Bachelor of Science with Honours in theoretical physics at the Australian National University" Includes bibliographical references.
108

Bose-Einstein condensates on a magnetic film atom chip

Whitlock, Shannon. January 2007 (has links)
Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, Centre for Atom Optics and Ultrafast Spectroscopy, 2007. / A thesis submitted for the degree of Doctor of Philosophy, Centre for Atom Optics and Ultrafast Spectroscopy, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 2007. Typescript. Bibliography: p. 107-118.
109

Wave packet dynamics in atomic systems and Bose-Einstein condensates

Fabčič, Tomaž, January 2008 (has links)
Stuttgart, Univ., Diss., 2008.
110

Bose-Einstein condensation in micro-potentials for atom interferometry

Scharnberg, Falk. January 2007 (has links)
Thesis (PhD) - Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, 2007. / Submitted in fulfilment of requirements for the degree of Doctor of Philosophy, [Faculty of Engineering and Industrial Sciences], Swinburne University of Technology, 2007. Typescript. Bibliography: p. [207]-224.

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