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 52 for “"Wave packet"”.
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Attosecond Wave Packet Metrology
… and molecules for the creation of ultrashort wave packets. Free electron wave packets can be controlled by an external laser field and driven to scatter off their parent ions. They also carry information on the atomic structure, which enables the phase-resolved characterization of unknown …
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A dissipative wave packet approach for unified nonlinear acoustics
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994.
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The scattering and shrinking of a Gaussian wave packet by delta function potentials
… by a random potential causes localization of wave functions, and that this localization is governed by the Born postulate of quantum mechanics. We begin with a simple model system: a one-dimensional Gaussian wave packet incident from the left onto a delta function potential with a single …
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Three-dimensional pulsed disturbances in a plane mixing layer.
… modulation of a spanwise uniform time-harmonic wave train which provides a clear phase reference for the phase-locked velocity measurements. The evolution of the pulsed disturbance depends critically on the time delay between the modulation pulse and the carrier wave train, the plane mixing …
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Strichartz estimates for the wave equation on Riemannian manifolds of bounded curvature
Wave packet methods have proven to be a useful tool for the study of dispersive effects of the wave equation with coefficients of limited differentiability. In this thesis, we use scaled wave packet methods to prove Strichartz estimates on compact Riemannian manifolds under the condition that the …
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Intensyvių femtosekundinių šviesos bangų paketų sklidimo Kero terpėse laikinis ir erdvinis charakterizavimas /
… temporal, spatial and spectral mapping of light wave-packet dynamics during the nonlinear propagation in transparent media, and enabled to observe and make accurate quantitative evaluation of the ultrafast change of medium properties. By means of high temporal (20 fs) and spatial (1 μm) …
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High Angular Momentum Rydberg Wave Packets
High angular momentum Rydberg wave packets are studied. Application of carefully tailored electric fields to low angular momentum, high- n ( n ∼ 300) Rydberg atoms creates coherent superpositions of Stark states with near extreme values of angular momentum, [cursive l]. Wave packet components orbit …
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Dynamics of interfering wave packets in rubidium by high resolution quantum beat spectroscopy
… spectroscopy has been realized to study atomic wave packet dynamics. Wave packets comprising pairs of low quantum number (n = 5 - 8) electronic states were formed in Rb vapor with ultrafast laser pulses, and their dynamics was observed by an all-optical technique of parametric four wave mixing …
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Nondispersive wave packets
In this work, nondispersive wave packet solutions to linear partial differential equations are investigated. These solutions are characterized by infinite energy content; otherwise, they are continuous, nonsingular and propagate in free space without spreading out. Examples of such solutions are …
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Excitation of wave packets and random disturbances in a boundary layer
A study on the behaviour of wave-packets and random disturbances, introduced by the vibrating-ribbon technique in a Blasius boundary layer, is presented. The experiments were conducted in the VPI & SU low turbulence wind tunnel. The flat plate model was constructed from an aluminum-paper honeycomb …
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Quantization of Chirikov map and quantum KAM theorem
… operator of this system. We find that the wave functions in the coherent state representation (CSR) are very similar to the classical trajectories. In particular, some of these wave functions have wall-like structure at the locations of classical KAM curves. We also find that a local …
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Neutrino Oscillations: Eighty Years In Review
… of neutrino oscillations as treated in the wave packet formalism.</p> <p>We have amassed here the principle theories and experimental results -- a mere tip of the iceberg -- that have brought us to our current understanding of neutrino oscillations. We have also studied the quantum mechanics …
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Computational Solutions of the Forward and Adjoint Euler Equations with Application to Duct Aeroacoustics
… the acoustic sources are modeled by a broadband wave packet. Radiation of acoustic waves at all frequencies can be obtained by Time Domain Wave Packet (TDWP) method in a single time domain computation. The TDWP method is also particularly useful for computations in the ducted or waveguide …
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Limits of long wavelength High Harmonic Generation
Many researchers are pushing for long wavelength driver pulses for High Harmonic Generation (HHG). The advantage of longer wavelengths is that the cut-off of the harmonic spectrum can be increased without the need for large electric fields. Large electric field is undesirable because it leads to …
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Fourier decoupling for convex sequences
… 𝑔′′(𝑥) > 0 for every 𝑥 ∈ [0, 1]. We utilize the wave packet structure of functions with frequency support in a neigh- borhood of an arithmetic progression.
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Quantum dynamics in laser–assisted collisions, laser–molecule interactions, and particle–surface scattering
… for up to three-dimensional problems. The wave packet propagation technique has been applied to ion – atom collisions in a strong laser field, the vibrational nuclear motion in small homonuclear diatomic molecular ions, and for the scattering of an ion in front of a metallic surface. For …
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Quantum Resonant Beats and Revivals in the Morse Oscillators and Rotors
… the quantum resonant beats and revivals of wave packet propagation. A concise way for exact prediction of the complete revival period of the Morse oscillator was given for the first time. It was suggested that any complete period was made of integer numbers of the minimum or fundamental …
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Manipulating Bose-Einstein condensates with laser light
… scattering was used to amplify atomic matter waves. The active medium was a Bose-Einstein condensate, pumped by off-resonant laser light ("Dressed condensate"). An atomic wave packet was amplified with a gain of 10 to 100. Phase-coherence of the amplifier was verified by observing the …
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Ultracold quantum gases in one-dimensional optical lattice potentials : nonlinear matter wave dynamics
… on experiments on the quantum dynamics of matter waves in a onedimensional lattice potential. A 87Rb Bose-Einstein condensates is prepared in a one-dimensional waveguide in the lowest band of a superimposed optical lattice potential. The action of a weak lattice potential allows to modify the …
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Chaotic behavior and energy polarisation in flatband lattice models
… symmetries, resulting in compactly localised wave functions to just a few lattice sites. The existence of FBs in materials entails high sensitivity to the initial conditions of the system, especially with regard to disorder and nonlinear- ity. In this study, we numerically investigate the wave …
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