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 187 for “"Ultracold"”.
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Ultracold molecules from ultracold atoms : interactions in sodium and lithium gas
… presents results from experiments in which ultracold Sodium-6 and Lithium-23 atomic gases were studied near a Feshbach resonance at high magnetic fields. The enhanced interactions between atoms in the presence of a molecular state enhance collisions, leading to inelastic decay and loss, …
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Ultracold Molecular Structure and Collisions
Ultracold molecules are instrumental in many fields of physics, such as high-resolution spectroscopy, quantum computation, and cold controlled chemistry. In this dissertation, we discuss the structure and collisions of ultracold molecules in the presence of external magnetic fields. We explore …
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Coherent manipulation of ultracold Rubidium
… and sensitive tests of quantum mechanics. Such ultracold temperatures may be reached by Doppler cooling which uses a velocity sensitive scattering force. This technique relies upon atoms which have closed electronic transitions between two states so that the atoms may continuously absorb photon …
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Light Propagation in Ultracold Atomic Gases
The propagation of light through an ultracold atomic gas is the main topic of the present work. The thesis consists of two parts. In Part I (Chapters 1,2,3), we give a complete description of the 1D photonic bands of a MI of two-level atoms paying attention to both band diagrams and reflectivity …
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Quasi-One-Dimensional Ultracold Fermi Gases
Ultracold atoms have become an essential tool in studying condensed matter phenomena. The advantage of atomic physics experiments is that they provide an easily tunable system. This experiment uses the lowest two ground state hyperfine levels of fermionic lithium. Having two different states …
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Early Dynamics of Ultracold Neutral Plasmas
… report new studies on the early-time dynamics of ultracold neutral plasmas. We use fluorescence spectroscopy to probe plasma dynamics on the nanosecond time scale. We determine the rms ion velocity during the initial plasma period. The initial ion acceleration is found as the time derivative of …
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Quantum Transport Experiments with Ultracold Atoms
… thesis describes a series of experiments with ultracold atoms in custom optical potentials, detailing quantum simulators developed for analysing the quantum transport properties of specific systems of interest. Two environments in particular are investigated: the quantum chaotic system of the …
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Ultracold fermionic atoms in disordered potentials
… apparatus to study disorder physics using ultracold fermionic atomic gases. We use this apparatus to realize 3D Anderson localization for the first time for quantum matter waves. We provide the first measurement of how the mobility edge—a hallmark of 3-dimensionality—and of localization …
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Momentum-space lattices for ultracold atoms
"As the progress of science pushes the frontiers of studying nature to both the extremely large scale and the incredibly small scale, experiments can become increasingly difficult to perform. Therefore, a scale model experiment for these kinds of physics can be useful as long as it is relatively …
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Quasicrystalline optical lattices for ultracold atoms
… regarding both growth processes and stability. Ultracold atoms in optical lattices offer an ideal, yet untested environment for investigating quasicrystals. Optical lattices, i.e. standing waves of light, allow the defect-free formation of a large variety of potential landscapes, including …
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Topological phenomena in ultracold atomic gases
… finding new ways to measure such consequences in ultracold atomic gas experiments. These experiments have significant advantages over the solid-state as ultracold atoms are controllable, tuneable and clean. They can also be used to investigate properties which are inaccessible in other quantum …
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Ultracold Fermi gas with repulsive interactions
This thesis presents results from experiments of ultracold atomic Fermi gases with repulsive interaction. Itinerant ferromagnetism was studied by simulating the Stoner model with a strongly interacting Fermi gas of ultracold atoms. We observed nonmonotonic behavior of lifetime, kinetic energy, and …
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Exploring spin physics with ultracold atoms
… neural networks, and more. Experiments with ultracold alkali atoms in optical lattices have realized spin models with great success. In particular, the isotropic Heisenberg model---the XXX model---was realized more than a decade ago. The ⁷Li apparatus described here was the first to realize a …
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Double-Loop Microtrap Array for Ultracold Atoms
… kind of magnetic microtrap is demonstrated for ultracold neutral atoms. It consists of two concentric loops of radii $r_1$ and $r_2$ having oppositely oriented currents. A magnetic field minimum is generated in three dimensions that can be used to trap the atoms with a trap depth of about 1 mK …
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Ultracold Bosonic Gases: Superfluidity and Quantum Interferometry
The aims of this dissertation are twofold. Firstly, the study of superfluidity, presented in the first part, has more a fundational character, since we investigate some well known problems, already raised in the context of superfluid helium, in order to gain a deeper understanding, by exploiting …
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Novel techniques for cold/ultracold molecular collisions
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This thesis presents the successful implementation of a slice velocity map imaging apparatus capable of performing molecular beam scattering experiments at collision energies from well above the room temperature to below 1 K. …
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Ultracold Molecules: The Effect of Electromagnetic Fields
… and chemistry communities in the properties of ultracold molecules. Electromagnetic fields can be used to create, trap, and modify the collisional dynamics of ultracold molecules, and thus the properties of ultracold molecules in electromagnetic fields is of growing importance. This thesis …
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Optical Detection of Ultracold Neutral Calcium Plasmas
… an optical method to detect calcium ions in an ultracold plasma. We probe the plasma with a 397 nm laser beam tuned to a calcium ion transition. The probe laser beam is focused to a 160 µm waist allowing fine spatial resolution. Ions are detected by measuring fluorescence using a …
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