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 10 of 10 for “"Bloch oscillations"”.
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Bloch-oscillating Electrons in Moiré Superlattices
… setting for realizing and probing electronic Bloch oscillations. A key property of Bloch oscillations of electrons in moiré systems is their two-dimensional character, described by several incommensurate frequencies rather than a single frequency. Crucially, although the frequencies of these …
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Theory of voltage oscillations in ultra-small capacitance Josephson junctions
… I to such a junction produces voltage or ""Bloch"" oscillations with a frequency WB = 211""1 /2e, which are the result of the periodic transfer a Cooper pair of charge 2e across the junction. This thesis examines certain theoretical aspects of these Bloch oscillations. Chapters 1 and 2 …
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Quantum Geometry and Topology in Periodically-Strained Graphene
… static electric field. Though analogous to Bloch oscillations, this novel oscillatory behavior is driven entirely by quantum geometry in momentum space instead of band dispersion. While the current from Bloch oscillations vanishes at large field strengths, the current from the geometric …
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Bogoliubov Excitations of Inhomogeneous Bose-Einstein Condensates
… Bogoliubov problem. In the second part, Bloch oscillations of Bose-Einstein condensates in presence of time-dependent interactions are considered. In general, the interaction leads to dephasing and destroys the Bloch oscillation. Feshbach resonances allow the atom-atom interaction to be …
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Geometry and Topology of Quantum States in Quasicrystalline Systems
… semiclassical picture, we find the presence of Bloch oscillations, usually synonymous with periodicity, alongside additional anomalous terms due to Berry curvature contributions. Fascinatingly, we also discover a so-called spiral holonomy in the effective band structure, in which circular …
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Terahertz-Strahlung auf der Basis beschleunigter Ladungsträger in GaAs
… of the bandstructure. Furthermore indications of Bloch oscillations were found by transport measurements. However, we could not measure a change of the dynamic conductivity when the electric field was toggled. Specific reasons for this and related experiments of other groups are discussed.
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Terahertz oscillation and stimulated emission from planar microcavities
… of the internal electric field - photonic Bloch oscillations - are successfully demonstrated. In combination with the anisotropic microcavities, this is a second concept for the modulation of transmitted light with terahertz frequencies. All experiments are accompanied by numerical or …
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Topological phenomena in ultracold atomic gases
… hence the trajectory of a wavepacket undergoing Bloch oscillations. Our general protocol allows a clean measurement from the semiclassical dynamics of the Berry curvature over the Brillouin zone. We discuss how this protocol may be implemented and explore the semiclassical dynamics for three …
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Transporte electrónico en nanoestructuras de carbono
… infinitas cavidades. Capítulo 4: Oscilaciones de Bloch. Este capítulo está dedicado al estudio del comportamiento de los electrones en nanotubos de carbono en presencia de un campo eléctrico constante unidimensional. En particular, nos centramos en la caracterización de las oscilaciones que …