Time-averaged optical potentials for creating and shaping Bose-Einstein condensates

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dc.identifier.uri http://dx.doi.org/10.15488/10073
dc.identifier.uri https://www.repo.uni-hannover.de/handle/123456789/10134
dc.contributor.author Albers, Henning ger
dc.date.accessioned 2020-09-18T08:37:11Z
dc.date.available 2020-09-18T08:37:11Z
dc.date.issued 2020
dc.identifier.citation Albers, Henning: Time-averaged optical potentials for creating and shaping Bose-Einstein condensates. Hannover : Gottfried Wilhelm Leibniz Universität, Diss., 2020, xvii, 95 S. DOI: https://doi.org/10.15488/10073 ger
dc.description.abstract The precision of atom interferometers, targeted for example in the Hannover Very Long Baseline Atom Interferometer (VLBAI) facility, imposes stringent requirements in several respects. They concern the control of center-of-mass motion and expansion of the wave packets by the matter-wave source as well as the number of atoms. By reducing the expansion, systematic errors, appearing e.g. through wavefront aberrations, can be lowered. These requirements can be matched by employing ultracold quantum gases or even quantum degenerate gases. A promising method to create those ensembles is evaporative cooling in a spatially modulated optical dipole trap. Here, the utilization of time-averaged potentials enables the fast creation of ultracold atomic ensembles with large number of atoms. Both, the higher number of atoms and the increased repetition rate, enhance the performance of the interferometer due to a lower quantum projection noise, which scales with 1/sqrt(N), and a larger bandwidth of the sensor due to faster sampling. The shaping of the matter-waves by techniques such as matter-wave lensing or Delta-Kick collimation is also feasible due to the dynamic control of the trapping potential. In this thesis the implementation and application of dynamic time-averaged optical potentials created via center position modulation of dipole trap beams is demonstrated. By evaporative cooling in these potentials, 1.9(0.4) x 10^5 condensed atoms with an expansion temperature of 29.2(1.3) nK were achieved after 3 s of evaporation. Up to 4.2(0.1) x 10^5 condensed atoms could be observed with slower evaporation of 5 s. Subsequent matter-wave lensing is carried out yielding expansion rates as low as 553(49) μms^-1 resulting in an effective temperature of 3.2(0.6) nK in two dimensions. This lens can be applied at any stage of evaporative cooling, thus short-cutting the generation of ultracold effective temperatures. In this thesis the limitations of optical matter-wave lensing in the current setup are revealed and ways to improve the performance are discussed. The fast generation of ultracold atomic ensembles will enhance the performance of the dual-species atom interferometer, which represents the experiment apparatus for this thesis and strives for a test of the Universality of Free Fall with an uncertainty on the order of 10^-9. The results of this thesis were used to test numerical simulations which were utilized to show the perspective of generating up to 10^6 collimated condensed atoms within 1 s of cycle time in the rubidium source system of Hannover’s VLBAI. eng
dc.language.iso eng ger
dc.publisher Hannover : Institutionelles Repositorium der Leibniz Universität Hannover
dc.rights CC BY 3.0 DE ger
dc.rights.uri http://creativecommons.org/licenses/by/3.0/de/ ger
dc.subject time-averaged optical potentials eng
dc.subject Bose-Einstein condensate eng
dc.subject matter-wave lensing eng
dc.subject zeitlich-gemittelte optische Potentiale ger
dc.subject Bose-Einstein Kondensate ger
dc.subject Materiewellen-Linse ger
dc.subject.ddc 530 | Physik ger
dc.title Time-averaged optical potentials for creating and shaping Bose-Einstein condensates eng
dc.title.alternative Zeitlich-gemittelte optische Potentiale zur Erzeugung und Manipulation von Bose-Einstein Kondensaten ger
dc.type doctoralThesis ger
dc.type Text ger
dc.description.version publishedVersion ger
tib.accessRights frei zug�nglich ger


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