Physics Commons^™

Generation, Dynamics, And Interaction Of Quartic Solitary Waves In Nonlinear Laser Systems, Sabrina Hetzel

Mathematics Theses and Dissertations

Solitons are self-reinforcing localized wave packets that have remarkable stability features that arise from the balanced competition of nonlinear and dispersive effects in the medium. Traditionally, the dominant order of dispersion has been the lowest (second), however in recent years, experimental and theoretical research has shown that high, even order dispersion may lead to novel applications. Here, the focus is on investigating the interplay of dominant quartic (fourth-order) dispersion and the self-phase modulation due to the nonlinear Kerr effect in laser systems. One big factor to consider for experimentalists working in laser systems is the effect of noise on the …

Numerical Calculation Of Losses Of Trapped Vortices Under Strong Rf Meissner Current And Dc Superheating Field In Type Ii Superconductors, Walive Pathiranage Manula Randhika Pathirana

Physics Theses & Dissertations

Research on the vortex dynamics and enhancing of superheating field in superconductors has attracted much attention in accelerator physics community to develop next-generation high-performance accelerator cavities. However, the extreme dynamics of curvilinear elastic vortices driven by very strong currents close to the depairing limit or superheating field of a superconductor with a nanostructured surface has not been well understood. We calculated the superheating field H_sh and critical momentum kc characterizing the wavelength of the instability λ_m of the Meissner state to flux penetration by solving numerically the Ginzburg-Landau equations. A bulk superconductor, superconductor with the inhomogeneous surface disorder …

Synergy Of Physics-Based Reasoning And Machine Learning In Biomedical Applications: Towards Unlimited Deep Learning With Limited Data, Valeriy Gavrishchaka, Olga Senyukova, Mark Koepke

Faculty & Staff Scholarship

Technological advancements enable collecting vast data, i.e., Big Data, in science and industry including biomedical field. Increased computational power allows expedient analysis of collected data using statistical and machine-learning approaches. Historical data incompleteness problem and curse of dimensionality diminish practical value of pure data-driven approaches, especially in biomedicine. Advancements in deep learning (DL) frameworks based on deep neural networks (DNN) improved accuracy in image recognition, natural language processing, and other applications yet severe data limitations and/or absence of transfer-learning-relevant problems drastically reduce advantages of DNN-based DL. Our earlier works demonstrate that hierarchical data representation can be alternatively implemented without NN, …

Practical Chaos: Using Dynamical Systems To Encrypt Audio And Visual Data, Julia Ruiter

Scripps Senior Theses

Although dynamical systems have a multitude of classical uses in physics and applied mathematics, new research in theoretical computer science shows that dynamical systems can also be used as a highly secure method of encrypting data. Properties of Lorenz and similar systems of equations yield chaotic outputs that are good at masking the underlying data both physically and mathematically. This paper aims to show how Lorenz systems may be used to encrypt text and image data, as well as provide a framework for how physical mechanisms may be built using these properties to transmit encrypted wave signals.

A Companion To The Introduction To Modern Dynamics, David D. Nolte

David D Nolte

Spatiotemporally Periodic Driven System With Long-Range Interactions, Owen Dale Myers

Graduate College Dissertations and Theses

It is well known that some driven systems undergo transitions when a system parameter is changed adiabatically around a critical value. This transition can be the result of a fundamental change in the structure of the phase space, called a bifurcation. Most of these transitions are well classified in the theory of bifurcations. Among the driven systems, spatiotemporally periodic (STP) potentials are noteworthy due to the intimate coupling between their time and spatial components. A paradigmatic example of such a system is the Kapitza pendulum, which is a pendulum with an oscillating suspension point. The Kapitza pendulum has the strange …

Effect Of Gain Saturation On The Nonlinear Dynamical Behavior Of Optically Injected Semiconductor Lasers, Furat Ahmad Al-Saymari, Imad Al-Deen Hussein Al-Saidi, May Jassim Ashoor

Turkish Journal of Physics

We studied numerically the dynamics and bifurcations route to chaos of an optically injected semiconductor laser. The sequence of bifurcations mainly followed the period-doubling scenario. Observations of different kinds of injected semiconductor laser dynamical behaviors including stable state, periodic oscillation state, quasi-periodic oscillation state, co-existence of periodic and chaotic states, and period-3 and period-6 oscillation states are reported. The existence of isolated branches created from a sudden jump in the dynamics of the semiconductor laser was also observed in the bifurcation diagram. In order to draw a detailed picture for the dynamical behavior of the semiconductor laser, we constructed color …

Tourbillion In The Phase Space Of The Bray-Liebhafsky Nonlinear Oscillatory Reaction And Related Multiple-Time-Scale Model, Zeljko D. Cupic

Zeljko D Cupic

The mixed-mode dynamical states found experimentally in the concentration phase space of the iodate catalyzed hydrogen peroxide decomposition (The Bray-Liebhafsky oscillatory reaction) are discussed theoretically in a related multiple-time-scale model, from the viewpoint of tourbillion. With aim to explain the mixed-mode oscillations obtained by numerical simulations of the various dynamical states of a model for the Bray-Liebhafsky reaction under CSTR conditions, the folded singularity points on the critical manifold of the full system and Andronov-Hopf bifurcation of the fast subsystem are calculated. The interaction between those singularities causes occurrence of tourbillion structure.

Black Hole Thermalization, D0 Brane Dynamics, And Emergent Spacetime, Paul L. Riggins '12, Vatche Sahakian

All HMC Faculty Publications and Research

When matter falls past the horizon of a large black hole, the expectation from string theory is that the configuration thermalizes and the information in the probe is rather quickly scrambled away. The traditional view of a classical unique spacetime near a black hole horizon conflicts with this picture. The question then arises as to what spacetime does the probe actually see as it crosses a horizon, and how does the background geometry imprint its signature onto the thermal properties of the probe. In this work, we explore these questions through an extensive series of numerical simulations of D0 branes. …

The Tangled Tale Of Phase Space, David D. Nolte

David D Nolte