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 13 of 13 for “"self-trapping"”.
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Ultracold quantum gases in one-dimensional optical lattice potentials : nonlinear matter wave dynamics
… the first experimental observation of nonlinear self-trapping for matter waves. The transition from the diffusive regime, characterized by an continuous expansion of the condensate, to the self-trapping regime is accomplished by increasing the atomic density. Due to the corresponding increase of …
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Mean-field theory for the dynamics of superfluid fermions in the BCS-BEC crossover
… first one is to study Josephson oscillations and self-trapping of superfluid fermions in a double-well potential with time-dependent Bogoliubov-de Gennes equations. We investigate the behaviour of a two-component Fermi superfluid. We numerically solve the time-dependent Bogoliubov-de Gennes …
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Properties of rotating ultracold bosonic quantum gases
… potential and thus exhibits macroscopic quantum self-trapping. Finally, we show that self-trapping is a direct manifestation of the behavior of the lowest-energy level.
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Bose-Einstein Condensates in a Single Double Well Potential
… tunnel back and forth between the wells, and the self trapping regime, where no tunneling is found. Furthermore, the investigation at finite temperature reveals, that the relative phase in steady state is not locked to zero but fluctuates according to its temperature and the tunneling coupling. By …
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Observation of nonlinear tunneling of a Bose-Einstein condensate in a single Josephson junction
… a consequence, the atomic distribution becomes self-locked and the relative phase evolves unbound in time. This regime of prohibited tunneling, which has no analogon in superconducting Josephson junctions, is called “macroscopic quantum self-trapping”.
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Localization and spreading of matter waves in disordered potentials
… spreading regimes: weak chaos, strong chaos and self-trapping. The spreading behaviour in these regimes is predicted theoretically and verified numerically. We also interpreted existing experimental data on the basis of our findings and showed that there is a qualitative agreement between our …
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Chaotic behavior and energy polarisation in flatband lattice models
… namely the weak chaos, strong chaos, and self trapping regimes. Using symplectic integration techniques, we evolve in time, t, initially localised wave packets for these regimes and quantify their spreading through the computation of the wave packets second moment, m2, while the extent of …
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Elementary processes in layers of electron transporting Donor-acceptor copolymers : investigation of charge transport and application to organic solar cells
… reveal that this behavior arises from a severe trapping of electrons in an exponential distribution of trap states. Based on the comparison of simulation and experiment, the general impact of charge carrier trapping on the shape of photo-CELIV and time-of-flight transients is discussed. In …
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The cold atom toolbox in momentum space
… in the momentum-space lattice, observing self-trapping in a double well system as well as on a full lattice, showing a skewed current-phase relationship in an analog to Josephson junction arrays, and investigating an interaction-induced shift in localization behavior under pseudodisorder. …
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Understanding and improving hole transport in hydrogenated amorphous silicon photovoltaics
… defective atomic structures and strong hole trapping. It is observed that a self-trapping defect arising from a reversible atomic rearrangement in the presence of a hole is most strongly correlated with deep trapping, followed by floating bonds, or over-coordinated silicon defects. Dangling …
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Developments and applications of THz polaritonics, efficient THz generation, and single-shot THz detection
… probe spectroscopy was used carrier self trapping. The results obtained here indicate that following photoexcitation liberated carriers are trapped on the 100s of femtosecond timescale. Lastly, optical pump single-shot terahertz probe measurements were used to study the dynamics of a …
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Spectroscopic Investigations of Light-Harvesting 2 Complexes from Rps. acidophila
… at least for some of the complexes an exciton self-trapping process is effective. In a subsequent experiment, series of emission spectra from individual LH2 complexes have been recorded at 1.2 K with a significantly improved spectral and temporal resolution. Drastic fluctuations of the emission …