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 17 of 17 for “"trap-depth"”.
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Experimental studies of evaporative cooling and Bose Einstein condensation in an optical trap
… loading phase of 60 ms about 1% of the atoms are trapped in a tight CO2 Laser focus region. Evaporative Cooling is optimized by lowering the dipole trap depth over a 7s period, leading to condensates of typically having 20000 atoms. In this thesis detailed characterization of the system and its …
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Towards a cryogenic planar ion trap for Sr-88
This thesis describes experiments with ion traps constructed with electrodes in a single two-dimensional plane, and ion traps operated in a cryogenic environment at 77K and 4K temperatures. These two technologies address needs which arise in developing potentially scalable approaches to quantum …
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Theory and application of planar ion traps
… thesis, we investigate a new geometry of Paul trap with electrodes in a plane. These planar ion traps are compatible with modern silicon microfabrication, and can be scaled up to large arrays with multiple trapping zones. We implement these designs on printed circuit boards with macroscopic …
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The dynamics of ultracold atoms in light-induced synthetic gauge fields
… We implement a model of atomic evaporation in a trapping potential, and we find optimal parameters for the trap depth and stiffness during evaporation. Using this model, we achieve a high efficiency of optical evaporation (γ<sub> eff</sub> = 4.0).^ Using that BEC, we study the dynamics of the BEC …
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Electrical properties and defect structures of praseodymium-cerium oxide solid solutions
… eV for 10% and 20% PCO samples. The measured trap depth was significantly higher (approximately 1.6 eV) in 0.5% and 1% PCO. The migration enthalpy for impurity band hopping conductivity was approximately 0.55 eV, slightly higher than the hopping enthalpy for intrinsic carriers in CeO2 (0.4 eV).
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Bose-Einstein condensates in optical lattices : the superfluid to Mott insulator phase transition
… studied as a function of momentum and lattice depth. Our phase diagram boundary extrapolates to the critical lattice depth for the superfluid-to-MI transition. When a one-dimensional gas was loaded into a moving optical lattice a sudden broadening of the transition between stable and unstable …
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Double-Loop Microtrap Array for Ultracold Atoms
A novel 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 …
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Construction of a quantum gas microscope for fermionic atoms
… resolution. We set up separate 3D magnetooptical traps for capturing and cooling both ²³Na and ⁴⁰K. These species are then trapped simultaneously in a plugged quadrupole magnetic trap and evaporated to degeneracy; we obtain a sodium Bose-Einstein condensate with about a million atoms and a …
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Some electrical properties of thin films of polypropylene formed by vacuum evaporation
… measurements there was evidence of electron trapping and the trap depth was estimated by using the thermally-stimulated current techniques, and was found equal to 0.33 eV. Thin films of evaporated polypropylene having thicknesses less than 1000Å, showed electroforming effects and electron …
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Laser Cooling of Antihydrogen
… (and thus velocity) of synthesized antihydrogen trapped in the laboratory setting is very large relative to the energy well depth of the trap providing the confining force. Accuracy of any measurements performed on trapped antihydrogen, and the complexity of future experiments, is sensitive to …
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Hydrogen Permeation Through Nickel And Nickel Alloys: Surface Reactions And Trapping
… by surface reactions or affected by internal trapping.<br></br><br></br>Analysis of data obtained for hydrogen permeation through nickel show that hydrogen is dissociatively chemisorbed in nickel.<br></br><br></br>The permeation parameters diffusivity, permeability and surface reaction rate …
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Investigation of Degradation Effects Due to Gate Stress in GaN-on-Si High Electron Mobility Transistors Through Analysis of Low Frequency Noise
… summing Lorentzian noise spectra from multiple traps leads to 1/f and random telegraph signal (RTS) noise. The primary cause of carrier fluctuations are electron traps near the 2DEG and in the AlGaN bulk. These traps occur naturally due to dislocations and impurities in the manufacturing …
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Charge-Storage mechanisms in polymer electrets
… electrets works and to identify the probable trap sites. Charge trapping and de-trapping processes were investigated in order to obtain evidence of the trap sites in polymeric electrets. The charge de-trapping behavior of two particular polymer electrets was studied by means of thermal and …
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Vertical flux, ecology and dissolution of radiolaria in tropical oceans : implications for the silica cycle
… and Panama Basin-PB) using PARLUX sediment traps in moored arrays at several depths. The taxonomic diversities of the radiolarian assemblages in the sediment traps were very high. A total of 420 taxa, including 23 newly identified taxa, were found at the three stations; of these, 208 taxa …
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Vertical flux, ecology and dissolution of radiolaria in tropical oceans : implications for the silica cycle
… and Panama Basin-PB) using PARFLUX sediment traps in moored arrays at several depths. The taxonomic diversities of the radiolarian assemblages in the sediment traps were very high. A total of 420 taxa, including 23 newly identified taxa, were found at the three stations; of these, 208 taxa …
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A new apparatus to simulate fundamental interactions with ultracold atoms
… the two miscible components |F = ±1⟩ if trapped by a spin-independent potential, avoiding the known phenomenon of â€TMbuoyancyâ€TM. Studying the dynamics of such systems for sufficiently long times, with a mixture subject to Zeeman differential energy shifts, requires a specific effort …
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Dynamics of internal nutrient loading in a eutrophic, polymictic lake (Lake Rotorua, New Zealand)
… (80 krn2), polymictic, eutrophic, shalJow (mean depth 10.8 m) lake in central North Island, New Zealand. Blooms of cyanobacteria and occasional anoxia of bottom waters are characteristic of the water quality in the lake during summer months (Dec-Mar.). This study examines the dynamics of internal …