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**Degree Discipline:**Physics

**Collection:**UNT Theses and Dissertations

### Application of the Finite Element Method to Some Simple Systems in One and Two Dimensions.

**Date:**May 2002

**Creator:**Hunnell, Jason C.

**Description:**The finite element method (FEM) is reviewed and applied to the one-dimensional eigensystems of the isotropic harmonic oscillator, finite well, infinite well and radial hydrogen atom, and the two-dimensional eigensystems of the isotropic harmonic oscillator and the propagational modes of sound in a rectangular cavity. Computer codes that I developed were introduced and utilized to find accurate results for the FEM eigensolutions. One of the computer codes was modified and applied to the one-dimensional unbound quantum mechanical system of a square barrier potential and also provided accurate results.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc3087/

### Application of the Wigner Formalism to a Slightly Relativistic Quantum Plasma

**Date:**August 1967

**Creator:**Harper, John H.

**Description:**A slightly relativistic fermion gas is described by the dynamical theory obtained from the Wigner distribution function. The problem is approached in a self-consistent manner including the two-body Darwin Hamiltonian. The goal is to find the departures from equilibrium and dispersion relations for wave propagation in the gas.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130850/

### Approach to Quantum Information starting from Bell's Inequality (Part I) and Statistical Analysis of Time Series Corresponding to Complex Processes (Part II)

**Access:**Use of this item is restricted to the UNT Community.

**Date:**May 2002

**Creator:**Failla, Roberto

**Description:**I: Quantum information obeys laws that subtly extend those governing classical information, making possible novel effect such as cryptography and quantum computation. Quantum computations are extremely sensitive to disruption by interaction of the computer with its environment, but this problem can be overcome by recently developed quantum versions of classical error-correcting codes and fault-tolerant circuits. Based on these ideas, the purpose of this paper is to provide an approach to quantum information by analyzing and demonstrating Bell's inequality and by discussing the problems related to decoherence and error-correcting. II: The growing need for a better understanding of complex processes has stimulated the development of new and more advanced data analysis techniques. The purpose of this research was to investigate some of the already existing techniques (Hurst's rescaled range and relative dispersion analysis), to develop a software able to process time series with these techniques, and to get familiar with the theory of diffusion processes.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc3092/

### Backscattering from Prolate Spheroids at Microwave Frequencies

**Date:**1956

**Creator:**Sybert, Jim

**Description:**This thesis examines backscattering from prolate spheroids at microwave frequencies.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc107919/

### Ballistic Deposition: Global Scaling and Local Time Series.

**Date:**December 2003

**Creator:**Schwettmann, Arne

**Description:**Complexity can emerge from extremely simple rules. A paradigmatic example of this is the model of ballistic deposition (BD), a simple model of sedimentary rock growth. In two separate Problem-in-Lieu-of Thesis studies, BD was investigated numerically in (1+1)-D on a lattice. Both studies are combined in this document. For problem I, the global interface roughening (IR) process was studied in terms of effective scaling exponents for a generalized BD model. The model used incorporates a tunable parameter B to change the cooperation between aggregating particles. Scaling was found to depart increasingly from the predictions of Kardar-Parisi-Zhang theory both with decreasing system sizes and with increasing cooperation. For problem II, the local single column evolution during BD rock growth was studied via statistical analysis of time series. Connections were found between single column time series properties and the global IR process.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc4392/

### Boundary Scattering of Electrons in Thin Cadmium Single Crystals

**Date:**August 1968

**Creator:**Fortmayer, Gary William

**Description:**In the present investigation, zinc was plated onto a cadmium crystal to determine the effect on the scattering parameter.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130996/

### Broad-band Light Emission From Ion Implanted Silicon Nanocrystals Via Plasmonic and Non-plasmonic Effects for Optoelectronics

**Date:**December 2012

**Creator:**Singh, Akhilesh K.

**Description:**Broad band light emission ranging from the ultraviolet (UV) to the near infrared (NIR) has been observed from silicon nanoparticles fabricated using low energy (30-45 keV) metal and non-metal ion implantation with a fluence of 5*1015 ions/cm2 in crystalline Si(100). It is found from a systematic study of the annealing carried out at certain temperatures that the spectral characteristics remains unchanged except for the enhancement of light emission intensity due to annealing. The annealing results in nucleation of metal nanoclusters in the vicinity of Si nanoparticles which enhances the emission intensity. Structural and optical characterization demonstrate that the emission originates from both highly localized defect bound excitons at the Si/Sio2 interface, as well as surface and interface traps associated with the increased surface area of the Si nanocrystals. The emission in the UV is due to interband transitions from localized excitonic states at the interface of Si/SiO2 or from the surface of Si nanocrystals. The radiative efficiency of the UV emission from the Si nanoparticles can be modified by the localized surface plasmon (LSP) interaction induced by the nucleation of silver nanoparticles with controlled annealing of the samples. The UV emission from Si nanoclusters are coupled resonantly to the LSP ...

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc177255/

### Brownian Movement and Quantum Computers

**Access:**Use of this item is restricted to the UNT Community.

**Date:**December 2004

**Creator:**Habel, Agnieszka

**Description:**This problem in lieu of thesis is a discussion of two topics: Brownian movement and quantum computers. Brownian movement is a physical phenomenon in which the particle velocity is constantly undergoing random fluctuations. Chapters 2, 3 and 4, describe Brownian motion from three different perspectives. The next four chapters are devoted to the subject of quantum computers, which are the signal of a new era of technology and science combined together. In the first chapter I present to a reader the two topics of my problem in lieu of thesis. In the second chapter I explain the idea of Brownian motion, its interpretation as a stochastic process and I find its distribution function. The next chapter illustrates the probabilistic picture of Brownian motion, where the statistical averages over trajectories are related to the probability distribution function. Chapter 4 shows how to derive the Langevin equation, introduced in chapter 1, using a Hamiltonian picture of a bath with infinite number of harmonic oscillators. The chapter 5 explains how the idea of quantum computers was developed and how step-by-step all the puzzles for the field of quantum computers were created. The next chapter, chapter 6, discus the basic quantum unit of information ...

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc4660/

### A Calculation of the Kaon-Neutron Scattering Cross Section

**Date:**June 1966

**Creator:**Hooper, Robert Gibson

**Description:**The purpose of this investigation was to study the scattering processes of K+ mesons with neutrons. In order to do such a study one must first make certain basic assumptions about the type of interaction involved and then proceed to calculate physically meaningful qualities which describe the processes. Thus, the problem is this: assuming the validity of Feynman's rules for these strongly interacting particles, calculate the differential and total scattering cross sections for the interaction of scalar K+ mesons and neutrons.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc130687/

### Carbon Contamination Measurements in Single Silicon Crystals

**Date:**December 1970

**Creator:**Logsdon, Lawrence E.

**Description:**The intent of this investigation was to directly measure the amount of carbon contamination in a single silicon crystal and, in so doing, develop a mathematical procedure that would be applicable to other contaminants in other substances.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131331/