Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 78 for “"Bose-Einstein condensate"”.
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Tunneling Dynamics of a Bose-Einstein Condensate
… possibility to study the decay of quasi-bound condensates via tunneling. We develop a novel trapping configuration for this purpose, in which the barrier acts as one of the walls of the trap. Inter-atomic interactions strongly dictate the escape dynamics of the condensate out of this trap, …
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A tunable Bose-Einstein condensate for quantum interferometry
The subject of this thesis is the use of BECs for atom interferometry. The standard way atom interferometry is today performed is by interrogating free falling samples of atoms. The employed samples are cold (but not condensed) to have high coherence, and dilute, not to interact significantly with …
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Creation of an all-optical Bose-Einstein condensate
… the creation of a large all-optically cooled Bose-Einstein condensate as a proof of the temperatures and densities achieved. In most cold atoms experiments, the Bose-Einstein condensate is achieved by evaporating the atoms in a magnetic trap.;Due to the swallowness of magnetic traps, the …
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Progress Towards a Spinor Bose-Einstein Condensate Machine
… atomic physics with the discovery of the first Bose-Einstein condensates (BECs) in 1995. These ultracold atomic vapors allow for study of fundamental quantum electromagnetic properties of atoms that are otherwise inaccessible due to large thermal energy fluctuations disrupting the quantum state. …
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Exploring Matter-wave Dynamics with a Bose-Einstein Condensate
Bose-Einstein condensates of dilute gases provide a rich and versatile platform to study both single-particle and many-body quantum phenomena. This thesis describes several experiments using a Bose-Einstein condensate of Rb-87 as a model system to study novel matter-wave effects that traditionally …
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A Trapped Single Ion Inside a Bose-Einstein Condensate
… We immerse a single trapped Yb+ ion in a Bose-Einstein condensate of Rb atoms. Our hybrid setup consists of a linear RF-Paul trap which is overlapped with a magnetic trap and an optical dipole trap for the neutral atoms. A first synergetic effect is the sympathetic cooling of the trapped …
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Atoms and Molecules Immersed in a Bose-Einstein Condensate
… in their absolute ground state directly from Bose polarons, which are dressed fermionic ⁴⁰K impurities immersed in a ²³Na Bose-Einstein condensate. In contrast to Feshbach molecules, Bose polarons at negative scattering length are long-lived in the presence of the BEC. We demonstrate direct …
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Formation and decay of a Bose-Einstein condensate in atomic hydrogen
The formation and decay of a Bose-Einstein condensate (BEC) in atomic hydrogen is studied. Magnetically trapped hydrogen atoms were evaporatively cooled close to the onset of Bose-Einstein condensation and then suddenly quenched below the transition temperature. The subsequent condensate formation …
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Impurities in a Bose-Einstein condensate using quantum Monte-Carlo methods: ground-state properties.
… properties of impurities immersed in a dilute Bose gas at zero temperature using quantum Monte-Carlo methods. The interactions between bosons are modeled by a hard sphere potential with scattering length a, whereas the interactions between the impurity and the bosons are modeled by a …
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Observation of nonlinear tunneling of a Bose-Einstein condensate in a single Josephson junction
… implementation of a Josephson junction for Bose-Einstein condensates. The weak link between two BECs constitutes the nonlinear generalization of the well known Josephson junction of weakly-coupled superconductors that are separated by a thin insulating barrier. In our experiment, the …
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Transport properties of a Bose-Einstein condensate with tunable interactions in the presence of a disordered or single defect potential
Bose-Einstein condensates (BECs) have proven to be remarkable systems with which to study some of the foundational models of condensed matter physics. The observation of a critical velocity for the breakdown of superfluidity in a BEC and the superfluid to Mott insulator transition observed in a BEC …
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Bose-Einstein condensation in a robust microtrap -- the combination of wire traps and atom chips
… about the successful creation of a Rubidium Bose-Einstein condensate. We use so called magnetic wire traps, which are especially simple, as they consist out of a wire and a homogeneous bias field. These wire traps are especially suited for Bose-Einstein condensation. Furthermore complex …
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Ultracold quantum gases in three-dimensional optical lattice potentials
… many body physics of ultracold atomic gases. A Bose-Einstein condensate is loaded into a three-dimensional optical lattice potential formed by a standing wave laser light field. In this novel quantum system we have been able to both realize a quantum phase transition from a superfluid to a Mott …
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Realization of Bose-Einstein condensation with Lithium-7 atoms
… of Lithium-7 atoms and the realization of the Bose- Einstein condensate as a first step to study quantum magnetism in optical lattice. The techniques used in this experiment include Zeeman slowing, magneto-optical trapping (MOT), gray molasses, static magnetic trapping, evaporative cooling, …
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Phases of bosons in optical lattices and coupled to artificial gauge fields
… the curious phases and novel properties of Bose-Einstein Condensate with optical lattices, and Bose-Einstein Condensate with light-induced artificial spin-orbit coupling. In this thesis, we report our research on these two types of boson systems. In the first topic, in contrast with …
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Studying coherence in ultra-cold atomic gases
… investigated include a thermal cloud of atoms, a Bose-Einstein condensate and a fermion pair condensate. In each case, a different type of measurement is performed. However, all of the experiments share a common tool: an optical lattice which is used to probe these atomic gases. In the first case, …
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Quantum properties of black hole
… research, it is on the analogue model of Bose Einstein condensate of gravitons. In my investigation with different approach I could reach similar conclusion for Schwarzschild radius which is derived for Bose Einstein condensate of N-gravitons . I could calculate the pressure inside the …
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Spin-orbit coupled Bose-Einstein condensates with observation of a stripe phase
… diagram of a 1-dimensional spin-orbit coupled Bose- Einstein condensate shows several interesting phases including the stripe phase. We find the stripe phase particularly interesting because the condensate develops a density modulation in free space while remaining superfluid, which are the …
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Manipulating Bose-Einstein condensates with laser light
A dilute gas Bose-Einstein condensate was probed and manipulated by off-resonant laser beams. Spontaneous and stimulated off-resonant light scatterings were studied experimentally. Stimulated, two-photon Bragg scattering was used for spectroscopic measurement of the mean-field energy and of the …
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