Physics Commons^™

Investigating The Influence Of Interface And Vacancy Defects On The Growth Of Silicon Quantum Dots In Sio2, John Phelan

Electronic Thesis and Dissertation Repository

The effects of interface and vacancy defects on silicon quantum dot (Si-QD) growth are investigated using measurements of Time Resolved Photoluminescence (TRPL), Photoluminescence (PL) Spectroscopy and Electron Paramagnetic Resonance (EPR). Thermally grown SiO₂ thin films (280nm) were irradiated with high energy (400keV – 1MeV) silicon ions in order to introduce defects into the Si-QD growth layer of SiO₂. A noticeable increase in PL emission intensity is seen with the highest energy pre-implanted sample over a single implant sample. TRPL results show increased radiative lifetimes for the lower energy (400keV) pre-implant while little or no difference is seen …

The Study Of Nanophotonic Switching Mechanisms In Photonic And Metallic Heterostructures, Joel Cox

Electronic Thesis and Dissertation Repository

In this thesis, nanophotonic switching mechanisms and light-matter interactions are explored in photonic and metallic heterostructures and nanocomposites. These heterostructures are made using various combinations of photonic crystals (PCs), quantum dots (QDs), and graphene or metal nanoparticles (MNPs).

PC heterostructures are formed by combining different PCs so that photons in a specific energy range can propagate in certain regions along one direction and cannot propagate in others. This band structure engineering is used to form photonic quantum wells (PQWs) that have discrete energy states along one dimension. By simulating the photon transmission along the direction of confinement, resonant photon tunnelling …

Controllability Of Open Quantum Optical Systems: Photon Fock States In A Cavity, Byron Henry Lowry

Doctoral Dissertations and Master's Theses

There has always been a signicant interest in using optical systems to control quantum phenomena. A major barrier to controllability of quantum optical systems is the fact that the systems are usually innite dimensional open systems, two cases which have mostly negative controllability results. This thesis develops three new denitions of controllability and reformulates a previous controllability theorem in order to apply the theorem to the system of interest. Then, the controllability of a pumped dissipative quantum optical cavity with engineered decoherence is investigated using previously developed concepts in quantum control theory, as well as the ones developed in this …

Contributions To The Cuore Collaboration, Samuel Joseph Meijer

Physics

This paper describes work done between 2010 and 2013 to contribute to the CUORE collaboration, a physics collaboration searching for neutrinoless double-beta decay in tellurium. Measurement of this decay would indicate fundamental information about the nature of the neutrino. The implementation of a parylene-coated detector frame is described. Also, a temperature stabilization system for an automated gluing system was constructed. An image recognition algorithm is described for locating spots of glue and evaluating their acceptability.

Hilbert Space Theory And Applications In Basic Quantum Mechanics, Matthew Gagne

Mathematics

We explore the basic mathematical physics of quantum mechanics. Our primary focus will be on Hilbert space theory and applications as well as the theory of linear operators on Hilbert space. We show how Hermitian operators are used to represent quantum observables and investigate the spectrum of various linear operators. We discuss deviation and uncertainty and briefly suggest how symmetry and representations are involved in quantum theory.

Quantum Resonant Beats And Revivals In The Morse Oscillators And Rotors, Zhenhua Li

Graduate Theses and Dissertations

Analytical eigenfunctions and eigenvalues for the Morse oscillator were applied to investigate 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 period. Within the fundamental period, the anharmonicity of this oscillator appeared to cause interesting space-time phenomena that include relatively simple Farey-sum revival structures. In addition, a simple sum of two Morse oscillators led to a double-Morse well whose geometric symmetry …

Superfluidity In Neutron Stars, Samuel J. Witte

Undergraduate Theses—Unrestricted

Nucleon pairing is studied with specific considerations directed toward the possible influence on neutron star cooling. We present an in-depth analysis of BCS theory using realistic nuclear potentials and consider the impact short-range correlations can have on the gap. Gap calculations are incorporated into neutron star cooling simulations and the significance of the 3P2 −3F2 channel in various hadronic cooling models is closely examined. An analysis of the 1S0 gap in neutron matter suggests short-range correlations can drastically alter the magnitude, density range, and temperature dependence of the gap. While the newly constructed 1S0 gap does not significantly alter the …

On The Physical Explanation For Quantum Computational Speedup, Michael Cuffaro

Electronic Thesis and Dissertation Repository

The aim of this dissertation is to clarify the debate over the explanation of quantum speedup and to submit, for the reader’s consideration, a tentative resolution to it. In particular, I argue that the physical explanation for quantum speedup is precisely the fact that the phenomenon of quantum entanglement enables a quantum computer to fully exploit the representational capacity of Hilbert space. This is impossible for classical systems, joint states of which must always be representable as product states. I begin the dissertation by considering, in Chapter 2, the most popular of the candidate physical explanations for quantum speedup: the …

Quantum Programming In Python: Quantum 1d Simple Harmonic Oscillator And Quantum Mapping Gate, Matthew Hoff

Physics

A common problem when learning Quantum Mechanics is the complexity in the mathematical and physical concepts, which leads to difficulty in solving and understanding problems. Using programming languages like Python have become more and more prevalent in solving challenging physical systems. An open-source computer algebra system, SymPy, has been developed using Python to help solve these difficult systems. I have added code to the SymPy library for two different systems, a One-Dimensional Quantum Harmonic Oscillator and a Quantum Mapping Gate used in Quantum Computing.

Density Functional Theory And The Calculation Of Tcmg2O4 Spinel Lattice Parameters, Jon Karlo Macias

Physics

The cohesive energy, lattice constant and bulk modulus of two simple HCP crystal structures of magnesium and technetium were calculated using the vienna ab initio simulation package (VASP) which is based on density functional theory (DFT). The same properties were determined for TcMg₂O₄ spinel. The theoretical results of the lattice constant of the pure crystals were compared to experimental results and found to be in excellent agreement with a difference of less than 2%. The results for the lattice constant of the TcMg₂O₄ spinel were found to be in excellent agreement as well with …

The Study Of Optoelectronics In Semiconductor And Metallic Nanoparticle Hybrid Systems, Daniel G. Schindel

Electronic Thesis and Dissertation Repository

This thesis examines optoelectronics of photonic crystals and photonic nanofibers, especially with quantum dots and metallic nanoparticles doped into them. The simulations produced focus on the quantum dots, which are presented in an ensemble of 3-level systems.

In order to consider a photonic nanofiber in isolation, a model was developed for the density of photonic states. We studied two profiles, a square cross-section and a circular cross-section. In addition, we consider two architectures, one where a photonic crystal surrounds a dielectric fiber, and one where the fiber is another photonic crystal. We found several photonic nanofibers with a single bound …

Quantum Computing With Steady State Spin Currents, Brian Matthew Sutton

Open Access Theses

Many approaches to quantum computing use spatially confined qubits in the presence of dynamic fields to perform computation. These approaches are contrasted with proposals using mobile qubits in the presence of static fields. In this thesis, steady state quantum computing using mobile electrons is explored using numerical modeling. Firstly, a foundational introduction to the case of spatially confined qubits embodied via quantum dots is provided. A collection of universal gates implemented with dynamic fields is described using simulations. These gates are combined to implement a five-qubit Grover search to provide further insight on the time-dependent field approach. Secondly, the quantum …

Experimental Generation And Manipulation Of Quantum Squeezed Vacuum Via Polarization Self-Rotation In Rb Vapor, Travis Scott Horrom

Dissertations, Theses, and Masters Projects

Nonclassical states of light are of increasing interest due to their applications in the emerging field of quantum information processing and communication. Squeezed light is such a state of the electromagnetic field in which the quantum noise properties are altered compared with those of coherent light. Squeezed light and squeezed vacuum states are potentially useful for quantum information protocols as well as optical measurements, where sensitivities can be limited by quantum noise. We experimentally study a source of squeezed vacuum resulting from the interaction of near-resonant light with both cold and hot Rb atoms via the nonlinear polarization self-rotation effect …