This thesis describes the design, development, and implementation of a pulsed source of polarization-entangled photons using spontaneous parametric down-conversion in a Sagnac interferometer. A tangle of 0.9286 ± 0.0015, fidelity to the state (|10〉 + |01〉)/√2 of 0.9798 ± 0.0004 and a brightness of 597 pairs/s/mW were demonstrated. Spontaneous parametric down-conversion is a nonlinear optical process in which one photon is split into two lower-frequency photons while conserving momentum and energy, in this experiment nearly degenerate photons are produced. These photons are then interfered at the output beamsplitter of the interferometer, exchanging path entanglement for polarization entanglement and generating the desired polarization-entangled photon pairs.

The thesis analyses the process of pair annihilation into one photon in a laser pulse. The theory of how to include pulse shapes in Strong Field QED and the resulting cross section is presented. The cross section is calculated and estimated for lasers of ELI and XFEL facilites. It is found that the effect may be experimentally verifiable at high frequency XFEL facilities for very finely tuned particle kinematics, but negligible at high intensity optical laser facilities such as ELI.

This thesis describes the design, development, and implementation of a pulsed source of polarization-entangled photons using spontaneous parametric down-conversion in a Sagnac interferometer. A tangle of 0.9286 ± 0.0015, fidelity to the state (|10〉 + |01〉)/√2 of 0.9798 ± 0.0004 and a brightness of 597 pairs/s/mW were demonstrated. Spontaneous parametric down-conversion is a nonlinear optical process in which one photon is split into two lower-frequency photons while conserving momentum and energy, in this experiment nearly degenerate photons are produced. These photons are then interfered at the output beamsplitter of the interferometer, exchanging path entanglement for polarization entanglement and generating the desired polarization-entangled photon pairs.

Many applications in modern science need to transmit extremely massive amount of data over wide area networks. These data usually do not need stringent real-time requirements but require large bandwidth to finish transmission with unreasonable time. High-energy physics experiments and climate modeling and analysis are typical examples of such applications. As TCP is known to perform inefficiently over networks of large delay-bandwidth product, efficient transmission of this kind of massive, non-real-time data has been heavily studied in the past. The previous results work well in dedicated networks but will compete for fair share of bandwidth with normal TCP connections if they operate in the public networks. The objective of this thesis is to design a new transmission protocol for the above applications that can operate in the public networks without affecting normal TCP connections. The new protocol is called Rate Control Transmission Protocol (RCTP). The idea is to apply the packet-pair measurement technique to measure the bandwidth share in the network for the transmission. The sending rate is based on that measurement and is precisely compensated by the RTT variance measurement. Due to the RTT compensation, RCTP can efficiently utilize the unused bandwidth in the network while not affecting the normal TCP transmissions, making it perfect for transmitting massive, non-real-time data in the public networks.

Short Pulse equation derived by Schafer and Wayne is a nonlinear partial differential equation that describes ultra short laser propagation in a dispersive optical medium such as optical fibers. Some properties of this equation e.g. traveling wave solution and its soliton structure and some of its conserved quantities were investigated. Conserved quantities were obtained by mass conservation law, lax pair method and transformation between Sine-Gordon and short pulse equation. As a result, loop soliton characteristic and six conserved quantities were found.

In this thesis, we investigate the integrability properties of some evolutionary type nonlinear equations in (1+1)-dimensions both with commutative and non-commutative variables. We construct the recursion operators, based on the Lax representation, for such equations. Finally, we question the notion of integrability for a certain one-component non-commutative equation. [We stress that calculations in this thesis are not original.]

No description available.

Au-pair Aufenthalte haben in Europa schon eine lange Tradition und werden nach wie vor gern als Möglichkeit genutzt, um eine längere Zeit im Ausland zu verbringen und im engen Kontakt mit der Gastfamilie Sprache und Kultur des Gastlandes kennen zu lernen. Die Autorin geht davon aus, dass solche nicht zuletzt auch interkulturellen Erfahrungen Spuren im Leben und in den Lebensentwürfen der jungen Erwachsenen hinterlassen. Über die subjektive Bedeutung dieser Erfahrung sowie deren Auswirkung ist bisher nur wenig bekannt, daher widmet sich die vorliegende Untersuchung von autobiographischen Erzählungen und Weblogs der Rekonstruktion eben solcher subjektiven Erfahrungen, Deutungen sowie den Lebens­ent­würfen ehemaliger Au-pairs. Der qualitative Charakter der Arbeit zeigt sich unter anderem darin, dass die Analyse eng an dem subjektiven Selbst- und Weltverständnis der Befragten anknüpft. Ausgehend von den Motiven und Intentionen und damit der Ergründung des Entscheidungsprozesses für den Au-pair Aufenthalt werden das Leben im Ausland, die Rückkehr und Wiedereingliederung sowie die Bedeutung des Auslandsaufenthaltes betrachtet. Der Auslandsaufenthalt wird als ein ‚Leben in einer anderen Welt’ konstruiert, in der insbesondere soziale Beziehungen und die Lebensführung der Gastfamilie maßgeblich zur Erfahrung und Konstruktion von (kultureller) Differenz beitragen. Dabei erweist sich die räumliche Trennung zum Heimatort in wesentlich stärkerem Maße bedeutsam als der Aufenthaltsort selbst. Der Au-pair Aufenthalt eröffnet den Au-pairs eine Erfahrungswelt, die im Zuge der Entwicklung neuer sozialer Rollen das Selbst- und Weltverhältnis verändert und mit Gefühlen von Freiheit und Selbstbestimmung, aber auch Angst und Heimweh verbunden wird. Zudem handelt es sich um ein Lern- und Entwicklungsfeld, welches nicht zuletzt auch an spezifische Entwicklungs­aufgaben des Jugend- und frühen Erwachsenenalters anknüpft. Interessant erscheinen insbesondere die Übergänge vom Heimatland ins Gastland und zurück. Diese Übergänge stellen sich als Bruchstellen dar, die als eine gefühlte Grenze zwischen den zwei erlebten ‚Welten’ Reflexionsprozesse auslösen. Die vorliegende Untersuchung zeigt schließlich auch, dass die Lebensentwürfe der befragten jungen Frauen, nicht wie in der soziologischen Frauenforschung vielfach thematisiert im Dilemma der doppelten Lebensführung aufgehen. Vielmehr sind die Lebensentwürfe durch eine Auslandsorientierung gekennzeichnet, die eine komplexe Lebensplanung nur kurz- bis mittelfristig möglich macht.

Thesis (Ph. D.)--University of Oklahoma. / Includes bibliographical references.

Dramatic improvements in circuit integration technologies have resulted in a huge increase in the complexity of circuits that can be fabricated on a single integrated circuit(IC). The significance of the performance and reliability issues of interconnects has increased greatly demanding radically different solutions such a Three-Dimensional ICs are an elegant solution to the interconnect and device density issues in the current and future technology generations as they provide an additional dimension for packing the devices. This results in a direct reduction in the chip package area and the total wiring required to complete all the interconnections. More importantly, the number and the length of long, global wires are reduced significantlydue to the availability of the third dimension for routing purposes. But to fully exploit all the advantages associated with three-dimensional ICs, a good three-dim ensional packing of devices is needed. This greatly increases the importance of Floorplanning and Placement stages ofthe VLSI Physical Design process. There have been many initial attempts to develop a physical design framework for three-dimensional ICs but only a few of them focus on physical design for three-dimensional macro-cell based circuit designs. This work develops a novel genetic algorithm for performing both two-dimensional and three-dimensional macro-cell floorplanning. The genetic floorplanner employs two novel crossover operators. The first crossover operator (MTOX) is an unbiased stochastic search operator, while the second crossover operator (HOOX) is a heuristic operator that searches for floorplans with good area usage. Both the crossover operators can be applied transparently for both 2D and 3D floorplanning.Three mutation operators have been developed to work with the chosen floorplan representation scheme, namely Sequence Pairs. Despite the use of a comparatively s mall population size of 200, the genetic floorplanner achieves reduction in footprint area and wirelength for both 2D and 3D floorplanning as compared to some of the recent works in the literature. For 2D floorplanning, the genetic floorplanner achieves a 12 percent average reduction in total wirelength as compared to a Quadratic Programming based Floorplanner for a small 2 percent increase in area. For 3D floorplanning,the proposed floorplanner achieves a 11 percent average reduction in total wirelength and a 5 percent decrease in footprint area as compared to a Simulated Annealing based 3D floorplanner.