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Full-Text Articles in Physics
Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler
Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler
Electrical & Computer Engineering Faculty Publications
The time evolution of the ground state wave function of a zero-temperature Bose-Einstein condensate (BEC) gas is well described by the Hamiltonian Gross-Pitaevskii (GP) equation. Using a set of appropriately interleaved unitary collision-stream operators, a qubit lattice gas algorithm is devised, which on taking moments, recovers the Gross-Pitaevskii (GP) equation under diffusion ordering (time scales as length2). Unexpectedly, there is a class of initial states whose Poincaré recurrence time is extremely short and which, as the grid resolution is increased, scales with diffusion ordering (and not as length3). The spectral results of J. Yepez et al. …
Superfluid Turbulence From Quantum Kelvin Wave To Classical Kolmogorov Cascades, Jeffrey Yepez, George Vahala, Linda L. Vahala, Min Soe
Superfluid Turbulence From Quantum Kelvin Wave To Classical Kolmogorov Cascades, Jeffrey Yepez, George Vahala, Linda L. Vahala, Min Soe
Electrical & Computer Engineering Faculty Publications
The main topological feature of a superfluid is a quantum vortex with an identifiable inner and outer radius. A novel unitary quantum lattice gas algorithm is used to simulate quantum turbulence of a Bose-Einstein condensate superfluid described by the Gross-Pitaevskii equation on grids up to 57603. For the first time, an accurate power-law scaling for the quantum Kelvin wave cascade is determined: k-3. The incompressible kinetic energy spectrum exhibits very distinct power-law spectra in 3 ranges of k space: a classical Kolmogorov k-(5/3) spectrum at scales greater than the outer radius of individual quantum vortex …
Self-Consistent Determination Of Electronic Structure And Elementary Excitations Of Finite Modulation-Doped Superlattices, Roger H. Yu
All Faculty Scholarship for the College of the Sciences
A self-consistent framework for the study of the electronic level structure of finite superlattices has been proposed. One of the surface states (Tamm states) found in our calculation crosses the Fermi energy in the energy gap when the depletion effect near the surface increases. We have shown the existence of low-energy Tamm states in our calculation when the surface barrier is lower than that of the interior. The electronic excitations of the superlattice have been studied via the electron-energy-loss function within the random-phase approximation. Two plasmon modes (well above the phonon response frequency) due to the Tamm states have also …