Physical Sciences and Mathematics Commons^™

High-Resolution Spectroscopy Of Interstellar Lines And Comets, Chemeda Tadese Ejeta

Doctoral Dissertations

"The study of interstellar molecules such as CO is crucial because interstellar ices in the core of a pre-solar molecular cloud provide the starting point for volatile evolution in the protoplanetary disk. A record of the initial volatile composition of the protoplanetary disk can be obtained from the study of the chemical composition of cometary nuclei. Because of their long residence in the Oort cloud and infrequent passage through the inner solar system, long-period comets are one of the most primitive bodies in our solar system that can tell us about the composition of the early solar system. High-resolution infrared …

Analysis Of Ultra-Wideband Voltage Pulse Propagation On Dispersive Absorptive Transmission Lines, Katherine Aho

Graduate College Dissertations and Theses

Electromagnetic transient waves are pulsed events that occur when there is an abruptchange in the typical steady-state conditions on a transmission line. Digital pulses on integrated circuits and a lightning strike on overhead power lines are some examples of transient voltage pulses. Although transients occur within a very short time duration, they can propagate over long distances; much farther than a slowly-varying envelope signal can propagate. Lingering effects of transients can be damaging to electrical equipment if they are not properly mitigated. Despite the negative effects of transients, certain designed transient pulses may be used to an advantage in remote …

Synthesis And Characterization Of Quantum Materials, Yunsheng Qiu

Doctoral Dissertations

"In this study, attempts were made to grow quantum materials that have recently undergone a profound change of perspective. These materials are involved in intricate macroscopic properties rooted in the subtle nature of quantum physics. To explore our understanding of quantum materials, this study includes three projects: Magnetic Topological Insulators, Topological Superconductors, and high-temperature superconductors.

A Cr-doped Sb₂Te₃ is added to the category for the magnetic topological insulators project. Their transport properties are studied, and the origin of ferromagnetism is studied. Anomalous Hall effect is observed in the Hall measurements, and serval factors (cooling rate, dopant deficiency) …

Solutions To The Kaluza-Klein Field Equations, Abel Eshete

All Graduate Theses, Dissertations, and Other Capstone Projects

This Alternate Paper Plan explores Kaluza-Klein theory, a multidimensional framework designed to unify Einstein’s gravitational field theory and Maxwell’s electromagnetic field theory. The objectives of this research can be summarized in two key areas: The first objective is to present a comprehensive introduction to the compactified Kaluza-Klein theory. The second aim involves the application of differential geometry, specifically E ́lie Cartan’s tetrad formalism, to derive exact solutions in two distinct scenarios: a. A Levi-Civita spacetime, b. A general spherical system. Furthermore, Lagrangian and Hamiltonian formalism are utilized to define stability conditions and describe gravitational lensing and Precession of Perihelion within …

Development Of Low Threshold Germanium Detectors For The Search Of Low Mass Dark Matter, Pramod Acharya

Dissertations and Theses

This dissertation explores using high-purity germanium (Ge) crystals for low-mass dark matter (DM) detection, focusing on enhancing crystal quality and identifying key crystal growth parameters. The study assesses the electrical properties of refined Ge materials through Hall Effect measurements and uses machine learning to predict impurity profiles, achieving levels conducive to high-resolution DM detectors. Utilizing a planar Ge detector fabricated at Texas A$\&$M and operated at cryogenic temperatures at the University of Minnesota, the study reveals time-dependent internal charge amplification through impact ionization. Research on charge transport dynamics in a cryogenic p-type Ge detector uncovers evolving charge dynamics and cluster …

Simulation Studies Of Topological Defect Behavior In Rank-2 Anti-Symmetric Tensor Fields, Wyatt Carbonell

Physics, Astronomy and Geophysics Honors Papers

Lorentz-violating models are a class of theories in which a fundamental field breaks the underlying Lorentz symmetry of a system action by assuming a nonzero vacuum expectation value. In this work, we consider a model which achieves such a Lorentz violation through a rank-2, anti-symmetric tensor field. We present a derivation of the equations governing the time evolution of this tensor field, the specifications of a program capable of numerically simulating this evolution through the solving of differential equations, evidence for the success of our simulation in accurately representing the model, and evidence against the physical viability of such a …

Numerical Black Hole Solutions For A Timelike Bumblebee Field, Azadé Modaressi

Physics, Astronomy and Geophysics Honors Papers

This work builds on a paper by Casana et al. [1], in which they calculated an exact, spherically symmetric solution to the Einstein equations in the presence of a bumblebee vector field. We extend their solutions by introducing a timelike component to the vector field. We are able to obtain series solutions to the Einstein equation in the presence of this field. We then demonstrate that these solutions recover flat spacetime. Our results cast doubt on the physical viability of this model, but a more thorough proof is required.

The Science Of Gravitational-Wave Sources And Beyond Compact Binary Coalescences, Yanyan Zheng

Doctoral Dissertations

"This work focuses on the field of gravitational-wave astronomy by extending the scope of detectable sources beyond compact binary coalescences, All the gravitational-wave detections so far come from compact binary coalescences. Focusing on core-collapse supernovae as promising sources for short gravitational-wave transients, this work reports optically targeted searches for gravitational-wave emitted by core-collapse supernovae during the third observing run of the LIGO and Virgo detectors. It also predicts the search sensitivity for the ongoing fourth and forthcoming fifth observing runs. Moreover, the work introduces a novel computational framework for testing the spatial distribution of binary black hole sources, allowing for …

Pumping A Transition, Christopher Daniel Hallman

Senior Projects Spring 2024

This thesis is an exploration into the physical mechanism responsible for the acceleration experienced when pumping a ramp on a bicycle, skateboard, or related human-powered vehicle. Pumping is the technique by which one propels oneself on a ramp, which is very similar to the process of pumping a playground swing. It is my hypothesis that the acceleration one experiences when pumping a ramp is primarily due to the conservation of angular momentum, affected by altering ones moment of inertia relative to the focal point of the curve through which one is traveling. This report documents my attempt to accurately describe …

Effective Drag Coefficient Prediction On Single-View 2d Images Of Snowflakes, Cameron Hudson

Graduate College Dissertations and Theses

The drag coefficient of snowflakes is an crucial particle descriptor that can quantify the relationships with the mass, shape, size, and fall speed of snowflake particles. Previous studies has relied on estimating and improving empirical correlations for the drag coefficient of particles, utilizing 3D images from the Multi-Angled Snowflake Camera Database (MASCDB) to estimate snowflake properties such as mass, geometry, shape classification, and rimming degree. However, predictions of the drag coefficient with single-view 2D images of snowflakes has proven to be a challenging problem, primarily due to the lack of data and time-consuming, expensive methods used to estimate snowflake shape …

Robust Interventions In Network Epidemiology, Erik Weis

Graduate College Dissertations and Theses

Which individual should we vaccinate to minimize the spread of a disease? Designing optimal interventions of this kind can be formalized as an optimization problem on networks, in which we have to select a budgeted number of dynamically important nodes to receive treatment that optimizes a dynamical outcome. Describing this optimization problem requires specifying the network, a model of the dynamics, and an objective for the outcome of the dynamics. In real-world contexts, these inputs are vulnerable to misspecification---the network and dynamics must be inferred from data, and the decision-maker must operationalize some (potentially abstract) goal into a mathematical objective …

Leveraging Redundancy As A Link Between Spreading Dynamics On And Of Networks, Felipe Xavier Costa

Electronic Theses & Dissertations (2024 - present)

A constant quest in network science has been in the development of methods to identify the most relevant components in a dynamical system solely via the interaction structure amongst its subsystems. This information allows the development of control and intervention strategies in biochemical signaling and epidemic spreading. We highlight the relevant components in heterogeneous dynamical system by their patterns of redundancy, which can connect how dynamics affect network topology and which pathways are necessary to spreading phenomena on networks. In order to measure the redundancies in a large class of empirical systems, we develop the backbone of directed networks methodology, …

Computationally Modeling The Human-Structure Interaction Response Of An Occupied Cantilevered Structure, Brennan Smith

Honors Theses

There is a limited understanding of the impact that passive human occupants have on a dynamic structural system, referred to as Human-Structure Interaction (HSI). Cantilevers are naturally prone to excessive vibrations due to their long unsupported spans, and cantilevered structures such as those commonly found in the seating area of a stadium facility or concert hall are designed to support a high density of occupancy.

This study determined that HSI in cantilevered structures can be modeled using a simple two-degree-of-freedom system. The results of the model were validated by data that was collected on a small-scale laboratory structure intentionally designed …

Existence Of Well-Defined Pointer Observable Selects Tensor Product Factorizations Of Quantum Systems, Brian Lee

CMC Senior Theses

In the decoherence account of quantum mechanics, a choice of particular tensor product structure (a particular partition of system into subsystems) is assumed. We explore whether it is possible to relax this arbitrary choice by requiring that a valid tensor product structure admits a quasi-classical description. Such tensor product structures are said to be quasi-classical or decoherence-selected tensor product structures. This project generalizes a 2-qubit quasi-classical tensor product structure selection algorithm to an n-qubit selection algorithm, which allows us to, for the first time, consider the relationship between decoherence-selected tensor product structures and locality-selected tensor product structures. To generalize the …

Compton Scattering Of Mammographic Soft X-Ray Beams By Alkali And Transition Metal Salt Filters Produce X-Ray Interference Zones That May Have Treatment Potential For Localized Cancer Lesions, Subhendra N. Sarkar, Eric Lobel, Sabina Rakhmatova, Derbie Desir, Somdat Kissoon, Daler Djuraev, Katie Tam

Publications and Research

In breast x-ray imaging scattered radiation adds 50% of harmful radiation dose from anisotropic Compton scattering mechanism. We have been working with double layered inorganic salt materials that can induce Compton scattering to the incident mammographic x ray beams (in 20-30 kVp range) with adequate isotropy (angular control). Typically metal nitrates and alkali halide salt layers are shown here to cause low energy radiation interference zones with high and low photon intensities and local flux heterogeneity in terms of flux covariance. Spatial variation of low energy photon flux creates concentrated and sparse radiation zones that may be used to induce …

Momentech - Modern Explorations Of The Impulse-Momentum Theorem, Todd Gelbord

Publications and Research

Herein we outline the design and construction of an instructional laboratory demonstration of the conservation of linear momentum, by way of the Impulse-Momentum Theorem, utilizing small, commercially available accelerometers attached to microcontrollers. The set-up is equipped with small, OLED screens which are able to display real-time acceleration graphs. Furthermore, a template for an experiment involving this set-up is provided. We also explore various data analysis options for different levels of student sophistication.

Part Sm: Statistical Mechanics, Konstantin Likharev

Essential Graduate Physics

Includes: Review of Thermodynamics; Principles of Physical Statistics; Ideal and Not-So-Ideal Gases; Phase Transitions; Fluctuations; Elements of Kinetics

Part Qm: Quantum Mechanics, Konstantin Likharev

Essential Graduate Physics

Includes: Introduction; 1D Wave Mechanics; Higher Dimensionality Effects; Bra-ket Formalism; Some Exactly Solvable Problems; Perturbation Theories; Open Quantum Systems; Multiparticle Systems; Introduction to Relativistic Quantum Mechanics; Making Sense of Quantum Mechanics

Part Em: Classical Electrodynamics, Konstantin Likharev

Essential Graduate Physics

Includes: Electric Charge Interaction; Charges and Conductors; Polarization of Dielectrics; DC Currents; Magnetism; Time-Dependent Electromagnetism; Electromagnetic Wave Propagation; Radiation, Scattering, Interference, and Diffraction; Special Relativity; Radiation by Relativistic Charges

Part Cm: Classical Mechanics, Konstantin Likharev

Essential Graduate Physics

Includes: Review of Fundamentals; Lagrangian Formalism; A Few Simple Problems; Oscillations; From Oscillations to Waves; Rigid Body Motion; Deformations and Elasticity; Fluid Mechanics; Deterministic Chaos; A Bit More of Analytical Mechanics

Fall Forward, Spring Back: Drivers Of Synchrony In The Sea Star Crawl-Bounce Gait Transition, Brady R. Nichols

Honors Projects

The Froude number is the ratio of kinetic energy to gravitational potential energy used during locomotion and is often used to analyze gait transitions. Here, I compare and contrast the human walk-run gait transition, which occurs at a consistent Froude number of 1 because there exists a mechanical speed limit to walking, and the sea star crawl-bounce gait transition, which occurs around Froude numbers of 1*10^-3. In this thesis I investigate why sea stars exhibit two gaits despite lacking brains and moving at Froude numbers far below other known gait transitions, hypothesizing (1) that the crawl-bounce transition may be mechanical …

Advancements In Glitch Subtraction Systems For Enhancing Gravitational Wave Data Analysis: A Brief Review, Mohammad Abu Thaher Chowdhury

Physics and Astronomy Faculty Publications and Presentations

Glitches are transitory noise artifacts that degrade the detection sensitivity and accuracy of interferometric observatories such as LIGO and Virgo in gravitational wave astronomy. Reliable glitch subtraction techniques are essential for separating genuine gravitational wave signals from background noise and improving the accuracy of astrophysical investigations. This review study summarizes the main glitch subtraction methods used in the industry. We talk about the efficacy of classic time-domain techniques in real-time applications, like matched filtering and regression methods. The robustness of frequency-domain approaches, such as wavelet transformations and spectral analysis, in detecting and mitigating non-stationary glitches is assessed. We also investigate …

Phase Dependence Of Kerr-Based Parametric Amplification, Nathan G. Drouillard, Tj Hammond

Physics Publications

Kerr instability amplification can amplify over an octave of spectrum, a broad bandwidth supporting few-cycle pulses. However, dispersion management in this regime is crucial, and we explore the parameters required to maintain the ultrashort pulse undergoing amplification. At low pump intensities, we experimentally observe an interference between the strongly chirped supercontinuum seed and weakly amplified pulse, reproduced in our model by manipulating the seed dispersion. Extending our model to cases of high gain, our simulation predicts the dispersion is near zero, and the phase can be compensated preamplification to generate near-transform-limited amplified few-cycle pulses.We discuss chirping the seed pulse to …

Supercontinuum Amplification By Kerr Instability, Sagnik Ghosh, Nathan G. Drouillard, Tj Hammond

Physics Publications

The versatility of optical parametric amplifiers makes them excellent sources for ultrashort visible and infrared pulses that drive strong-field physics experiments. We extend four-wave optical parametric amplification to the strong-field regime, known as Kerr instability amplification, and experimentally verify the modified noncollinear conditions for optimum amplification. We confirm that Kerr instability amplification can be used to amplify spectra that span nearly an octave in a single beam. We also amplify the near-infrared portion of the spectrum to generate the third harmonic downstream.

Detection And Diagnosis Of Bacterial Pathogens In Blood Using Laser-Induced Breakdown Spectroscopy, E J. Blanchette, E A. Tracey, A Baughan, G E. Johnson, H Malik, C N. Alionte, I G. Arthur, M E. Pontoni, Steven Rehse

Physics Publications

The ability to rapidly and accurately detect and identify pathogenic bacteria in clinically-obtained blood specimens with laser-induced breakdown spectroscopy (LIBS) is evaluated. Samples of blood obtained from five patients in a local hospital were confirmed to be negative for the presence of bacteria by the pathology department and were then tested with LIBS. Specimens of blood were tested as obtained from the hospital with no other alteration as control samples and were also intentionally spiked with known aliquots of Escherichia coli, Staphylococcus aureus, Enterobacter cloacae, and Pseudomonas aeruginosa to simulate blood infections. LIBS spectra were acquired from blood deposited on …

Detection And Diagnosis Of Bacterial Pathogens In Urine Using Laser-Induced Breakdown Spectroscopy, E J. Blanchette, E A. Tracey, A Baughan, G E. Johnson, H Malik, C N. Alionte, I G. Arthur, M E. Potoni, Steven Rehse

Physics Publications

The presence of bacterial cells from three species has been detected in clinical specimens of human urine using laser-induced breakdown spectroscopy (LIBS) by using a partial least squares discriminant analysis (PLS-DA) of 360 spectra obtained from 12 specimens of infected urine and 239 spectra obtained from eight specimens of sterile urine. Nominally sterile urine specimens obtained from four patients at a local hospital after being screened negative for the presence of bacterial pathogens were spiked with known aliquots of Escherichia coli, Staphylococcus aureus, and Enterobacter cloacae to simulate clinical urinary tract infections. Fifteen emission line intensities measured from the LIBS …

Cross-Layer Design Of Highly Scalable And Energy-Efficient Ai Accelerator Systems Using Photonic Integrated Circuits, Sairam Sri Vatsavai

Theses and Dissertations--Electrical and Computer Engineering

Artificial Intelligence (AI) has experienced remarkable success in recent years, solving complex computational problems across various domains, including computer vision, natural language processing, and pattern recognition. Much of this success can be attributed to the advancements in deep learning algorithms and models, particularly Artificial Neural Networks (ANNs). In recent times, deep ANNs have achieved unprecedented levels of accuracy, surpassing human capabilities in some cases. However, these deep ANN models come at a significant computational cost, with billions to trillions of parameters. Recent trends indicate that the number of parameters per ANN model will continue to grow exponentially in the foreseeable …

Scattering Of Electromagnetic Radiation By Bianisotropic Spheres, Maxwell A. Wallace

Electronic Theses and Dissertations

Modern developments in materials science have led to the increased demand for the ability to control electromagnetic radiation at scales smaller than ever. One of the most important areas of research for controlling the manipulation of electromagnetic radiation, has been the studying of novel optical metamaterials, including the most general and complex form, bianisotropic metamaterials (BAMs). With modern developments in nano- engineering, paired with the advancement of more robust theoretical studies of BAMs, the demand for more novel BAM technologies has increased. With the advent of research of unbounded BAM media, as well as the recent extensions of Mie theory …

Novel Time Projection Chamber Techniques With Applications Towards Neutrinoless Double Beta Decay Searches, Nicholas K. Byrnes

Physics Dissertations

One of the highest priority endeavors in nuclear and particle physics is the search for Neutrinoless Double Beta Decay (0νββ). The observation of 0νββ would prove that the neutrino is a Majorana particle i.e. its own antiparticle, offering a mechanism by which the matter-antimatter asymmetry observed in our universe could be explained. This theoretical decay mechanism is only energetically favored in certain neutron-rich isotopes and, if found, would be the rarest decay process ever observed. To compete with the exceedingly long half-life of 0νββ, all contemporary searches are focused on the following detector performance metrics: Increasing the instrumented isotopic mass …

Microstructure-Based Modeling Of Primary Cilia Mechanics, Nima Mostafazadeh, Andrew Resnick, Y.-N. Young, Zhangli Peng

Physics Faculty Publications

A primary cilium, made of nine microtubule doublets enclosed in a cilium membrane, is a mechanosensing organelle that bends under an external mechanical load and sends an intracellular signal through transmembrane proteins activated by cilium bending. The nine microtubule doublets are the main load-bearing structural component, while the transmembrane proteins on the cilium membrane are the main sensing component. No distinction was made between these two components in all existing models, where the stress calculated from the structural component (nine microtubule doublets) was used to explain the sensing location, which may be totally misleading. For the first time, we developed …