Physics Commons^™

Critical Behavior Ofthedilutedquasi-Onedimensionalquantum Ising Model, Logan Bradley Sowadski

Masters Theses

We explore the phase transition in the diluted quasi-one-dimensional quantum Ising model. We begin by giving an introduction to the Ising model followed by derivations of the properties and observables. A brief overview of Monte-Carlo simulations is also given focusing on two algorithms that make simulations for physically realizable systems possible, the Metropolis and Wolff algorithms. We finally discuss the concept of random disorder in the system and the effects this can have on the bulk of the system.

These concepts are then directly applied to a quasi-one-dimensional Ising model. Motivated by recent experiments on the spin-chain material cobalt niobate, …

Synthesis And Analysis Of Materials For Quantum Devices, Mathew Pollard

Doctoral Dissertations

Quantum materials play a pivotal role in the advancement of next-generation technology. Superconducting quantum computing, dissipationless spintronics, or valleytronics offer promising ways forward beyond traditional chip miniaturization. Josephson Junctions (JJs) have already revolutionized quantum information and high precision detectors. Quantum systems, however, are either hard to control, produce, and/or maintain. This calls for a better understanding of microscopic properties and tuning of these quantum states.

In this work, we experimentally investigated growth methods to control the electric and magnetic properties of Topological Insulator (TI) Sb2Te3 through Cr-doping. Our results demonstrate the onset of a Magnetic Topological Insulator (MTI) and have …

Quantum And Classical Phase Transitions In Disordered Systems, Gaurav Ramesh Khairnar

Doctoral Dissertations

This work examines the effects of quenched disorder on classical and quantum phase transitions. There are countless examples of phase transitions in nature. Here, we study phase transitions in condensed matter with the help of simple models that focus on the essential unifying features of the problems. We are particularly interested in investigating how the presence of disorder changes the behavior of the system in the vicinity of a phase transition.

Here, we discuss three closely related problems regarding phase transitions. First we consider the behavior of highly diluted magnets with varying dilution levels in order to explain the unusual …

Measuring Resistivity With Low-Cost 3-D Printed Four-Point Probe, Benjamin Siens

SPARK Symposium Presentations

Resistivity is an intrinsic property that determines how strongly electrical current is resisted. Measurement of the resistivity of materials is vital for many fields of science and engineering. This is easily accomplished with a four-point probe. However, commercial probes can be costly. Using 3-D printing and based on the design in Lu et al. (J. Chem. Educ. 2017), a functional four-point probe has been built at a much lower cost in materials. Additionally, the probe design has been simplified for easier construction and better compatibility with Belmont University’s 3- D printers. ITO glass was used to determine the accuracy of …

Fortifying Nuclear Security: Cultivating Vigilance Culture Among Personnel For Enhanced Prevention And Response, Sabariah Kader Ibrahim, Sonia Naz

International Journal of Nuclear Security

A vigorous nuclear security culture is crucial in preventing the theft and sabotage of nuclear material. It requires vigilance from all employees because relying solely on closed-circuit television systems and security personnel is insufficient to deter potential threats. Employee attentiveness plays a vital role in recognizing and preventing suspicious activities. However, achieving a strong security culture is challenging because of the lack of incidents in some facilities, leading to employee complacency.

This paper highlights the pivotal role of personnel in the success of nuclear security measures, emphasizing the need for a proactive and vigilant mindset among staff. Through the analysis …

Optimal Control And Structurally-Informed Gradient Optimization Of A Custom 4-Dof Rigid-Body, Brock Marcinczyk, Logan E. Beaver

Mechanical & Aerospace Engineering Faculty Publications

This work develops a control-centric framework for a custom 4-DOF rigid-body manipulator by coupling a reduced-order Pontryagin’s Maximum Principle (PMP) controller with a physics-informed Gradient Descent stage. The reduced PMP model provides a closed-form optimal control law for the joint accelerations, while the Gradient Descent module determines the corresponding time horizons by minimizing a cost functional built directly from the full Rigid-Body Dynamics. Structural-mechanics reaction analysis is used only to initialize feasible joint velocities—most critically the azimuthal component—ensuring that the optimizer begins in a physically admissible region. The resulting kinematic trajectories and dynamically consistent time horizons are then supplied to …

Atmospheric Chemistry Experiment (Ace) Winds, Matthew Wyatt, Peter F. Bernath, Chris Boone, Léo Lavy, Ryan Johnson

Chemistry & Biochemistry Faculty Publications

The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) uses limb geometry to measure transmittance spectra of Earth's atmosphere by solar occultation. Line-of-sight wind speeds can be derived via Doppler shifts of molecular lines in infrared spectra. The wind look direction angles relative to geodetic North are derived from geometry. We validate the new ACE version 5.3 (v.5.3) line-of-sight winds with MIGHTI and meteor radar vector wind observations and find a ±15 m/s sunrise/sunset shift above 80 km. We also compare line-of-sight winds from ACE-FTS v.5.2 and v.5.3 with vector winds from the MERRA-2, HWM14, and WACCM-X models. A ±15 m/s …

Tidal Love Numbers For A Non-Rotating Two-Fluid Neutron Star: Interior Solution, Gregory G Jaurequi

Dissertations and Theses

We investigate the tidal Love numbers for a non-rotating dark matter admixed neutron star (NS). Tidal Love numbers, which quantify a star's response to the tidal field of a companion object, are an important feature in the gravitational wave (GW) signal and vary depending on the star’s equation of state and dark matter profiles. By determining how the internal properties of the NS affect the GW signal, we hope that improvements in gravitational wave detection will help constrain these parameters by providing additional data from neutron star mergers with other compact objects. To this end, we focus on solving the …

Co₂ Isotopologues From The Ace Satellite, D. English, P. Bernath, C. Boone

Chemistry & Biochemistry Faculty Publications

Carbon dioxide isotopologues have been studied thoroughly in the troposphere. In the stratosphere, the minor oxygen CO₂ isotopologues have anomalous abundances due to their exchange reactions with isotopically fractionated ozone, differentiating them from tropospheric CO₂. Previously a model predicted that this anomalous isotopic abundance continues into the mesosphere but lacked verification from experimental observations. Here we use the Atmospheric Chemistry Experiment Fourier Transform Spectrometer which records infrared transmittance spectra of the Earth's limb from low Earth orbit using solar occultation. These infrared spectra provide measurements of global CO₂ isotopologue volume mixing ratios (VMRs) from the upper troposphere to the lower …

Formation Of Pyramidal Palladium Enhanced By B(C₆F₅)₃ Additive Enabling Selective Alkene Monoisomerization, Paul D. Miller, Trandon A. Bender

Chemistry & Biochemistry Faculty Publications

The addition of a strong Lewis acid, tris(pentafluorophenyl)borane, facilitates the reduction of Pd(cod)Cl₂ with Et₃SiH to form palladium nanoparticles in organic solvents. It was found that these palladium nanoparticles are capable of selective monoisomerization of linear alkenes. This heterogeneous palladium catalyst is tolerant of a wide variety of functional groups, confirmed by substrate and robustness screenings. It is also possible to utilize poly(methylhydro)siloxane, an industrial waste byproduct, as the reductant to enable similar isomerization chemistry.

The Requirements Of A Nuclear Propulsion System For The Human Exploration Of Mars, Scotia Rollins

Pitzer Senior Theses

This thesis investigates the propulsion requirements for a crewed mission to Mars, focusing on how mission architecture, particularly the choice between opposition- and conjunction-class trajectories, influences the selection between nuclear thermal propulsion (NTP) and nuclear electric propulsion (NEP). By applying the Tsiolkovsky rocket equation, the Delta-V (∆V) needed for efficient interplanetary transfers is shown to exceed the performance limits of chemical propulsion, motivating the need for nuclear alternatives. An engineering comparison of NTP and NEP systems evaluates key parameters including specific impulse, thrust, propellant mass fraction, system mass, and power-to-mass ratios. NTP provides high thrust but moderate efficiency, making it …

A Distorted-Wave Approach To The Elastic Scattering Of Twisted Electrons, Allison Harris, Stephan Fritzsche

Faculty publications – Physics

The elastic scattering of spinless vortex electrons on realistic target atoms has been investigated. In particular, expressions are derived in different approximations for the angular distribution of elastically scattered electrons. We develop a distorted wave formalism that includes the effect of the atomic potential on the impinging vortex electron and compare this to a plane-wave Born approximation (PWBA) without such a distortion. Detailed computations have been performed for elastic scattering of vortex electrons on helium, neon, and argon targets by varying the energy, topological charge, and opening angle. Our results show that the overall magnitude of the angular distribution of …

Developments On Quantum Phase Space Dynamics And Foundations, Gabriel Nowaskie

Mahurin Honors College Capstone Experience/Thesis Projects

This work explores the development and unification of quantum theory within phase space, with a particular focus on new mathematical structures and solution techniques that extend the standard quantum formalism. Building upon the Quantum Phase Space Representation (QPSR) introduced by Torres-Vega and Frederick, we present several advancements that address longstanding gaps in the formulation and solvability of quantum systems in this framework. We introduce the Half-Transform Ansatz, a novel method for solving the Time-Independent Schrodinger Equation by recasting it into a hypergeometric form, enabling the application of the Nikiforov-Uvarov method. This approach is demonstrated through the analysis of quarkonium systems …

Dynamics Of Thermalization In Classical Three-Dimensional Many-Body Systems: Non-Maxwellian Distributions And The Role Of Anisotropic Trapping, Roberto Onofrio, Bala Sundaram

Data and Datasets

The physics of interacting baths is of interest in a variety of contexts, ranging from ultracold atoms to ionized gases. While many features can already be captured in a one-dimensional model, others are speci c to the situation of two or three-dimensional systems. In this paper, we focus on three-dimensional features of a model for thermalization between two baths that we have explored in earlier publications. In contrast to the one-dimensional situation we show that, enroute to thermalization, deviations from the Maxwell-Boltzmann energy distributions more akin to  -distributions are observed. In three dimensions, these can be seen in changes at …

Nonlinear Wave Dynamics In Asteroseismology With Application To Delta Scuti Stars, Mohammed Mourabit

Physics Dissertations - Archive

This thesis compiles the collection of works in nonlinear astroseismology and its implication to the δ Sct variable that we carried over the course of five years. With the advent of high-resolution space missions such as the Kepler and TESS telescopes, we were able to see significant progress in the field in recent years. Nonetheless the new technologies also brought an increasing number of observation that are seemingly contradictory to the linear theory of asteroseismology. In particular, we find the δ Sct variable, which eludes our models in terms of how varied we find they spectra for stars with very …

Evaluation Of The Stability Of Argan Oil Nanoemulsions Formulated And Optimized Through Experimental Design For Dermatological Applications, Yousra Mdarhri, Ikram Bouziane, Narjisse Mokhtari, Lama Rissouli, Ahmed Touhami, Fakhita Touhami, Mohamed Chabbi

Physics & Astronomy Faculty Publications

Argan oil is a highly sought-after natural product renowned for its therapeutic and rejuvenating properties. This study focused on harnessing its dermatological bioactivity by developing stable nanoemulsions through a simple low-energy method using a single non-ionic surfactant. The composition and properties of Argan oil were analyzed using High-Performance Liquid Chromatography (HPLC), Gas Chromatography (GC), and quality indexes, adhering to international standards. The effect of system composition on stability was evaluated using a pseudo-ternary phase diagram and Phase Inversion Composition (PIC) emulsification technique. Optimal process parameters for producing stable nanoemulsion were determined through Response Surface Methodology (RSM) analysis. The resulting nanoemulsions …

High Antarctic Coastal Productivity In Polynyas Revealed By Considering Remote Sensing Ice-Adjacency Effects, Hilde Oliver, Jessica S. Turner, Alexandre Castagna, Henry Houskeeper, Heidi Dierssen

OES Faculty Publications

Ocean color-based estimates of Antarctic net primary productivity (NPP) have indicated low nearshore productivity in ice-adjacent waters, contrasting with coupled physical–biogeochemical models. To understand this discrepancy, we assessed satellite records of polynya NPP by comparing field data with two satellite imagery datasets derived using different processing schemes. Our results indicate historical underestimation of chlorophyll a for imagery obtained using default atmospheric correction processing within approximately 100 km of ice-covered coastlines due to adjacency effects. Using radiative transfer modeling, we find that biases in ocean color polynya observations due to adjacency effects correspond to the high albedo of ice and snow. …

The Goddard Rocket Researches: A Photographic Record, Esther C. Goddard

The Goddard Rocket Researches: A Photographic Record [Photo Album]

This page contains a pdf scan of 'The Goddard Rocket Researches: A Photographic Record' in its entirety. The individual photographs and their descriptions can be seen here.

'The Goddard Rocket Researches: A Photographic Record' is an annotated photo album covering Robert H. Goddard's work and experimentation with rocketry. It was assembled and curated by Esther Goddard sometime after her husband's passing in 1945.

The vast majority of these photographs were taken by Esther herself. Esther was an avid camerawoman and photographer, and during Robert's lifetime she meticulously documented his life's work in rocketry--from experiments and instruments to processes and …

Mathematics And Determinism: Chaos, Quantum Mechanics, And The Limits Of Predictive Structure, Jackson T. Salumbides

CMC Senior Theses

This thesis examines the relationship between mathematics and determinism by analyzing how chaos theory, quantum mechanics, and formal mathematical limits challenge traditional conceptions of predictability and causal structure. Chaos theory shows that deterministic systems can exhibit practical unpredictability due to sensitivity to initial conditions. Quantum mechanics introduces probabilistic outcomes that complicate deterministic interpretation, though alternative frameworks such as Bohmian mechanics and superdeterminism attempt to restore determinism at conceptual cost. Additionally, results from mathematical logic, including Gödel’s incompleteness theorems and Turing’s undecidability, demonstrate intrinsic limitations on what can be deduced or computed, even in fully deterministic systems. By synthesizing these areas, …

Novel Methodology And Proof-Of-Concept For Proton Ct Using Spot Profile Rather Than Bragg Peak Location, Brett Albert Ruben

Open Access Dissertations

Proton radiation therapy offers a highly precise method for cancer treatment, theoretically providing superior dose deposition characteristics compared to conventional X-ray radiation therapy. Its steep and finite dose fall-off region allows for superior tumor coverage while reducing, though not eliminating, dose to surrounding healthy tissue. However, its full potential is limited by range uncertainties, particularly those arising from the reliance on X-ray-based imaging methods called computed tomography (CT) for proton-based treatment. CT image Hounsfield Units (HU) must be converted to stopping power ratios (SPR) as these ratios are the clinically relevant value for accurately planning particle interactions during proton therapy. …

Beyond The Phonon Gas Model (Pgm): Unraveling The Unique Mechanistic Processes Dictating Thermal Transport In Highly Anharmonic And Disordered Materials, Sandip Thakur

Open Access Dissertations

Thermal transport in nonmetallic solids has traditionally been described by the phonon gas model (PGM), in which heat is carried by weakly interacting phonon quasiparticles in an ordered crystalline lattice. However, this model breaks down in materials characterized by strong anharmonicity, dynamic disorder, or structural complexity, features prevalent in many next-generation materials used in energy conversion, optoelectronics, and thermal management. This dissertation investigates thermal transport in such complex materials, including metal halide perovskites (MHPs), covalent organic frameworks (COFs), metal organic frameworks (MOFs), and 2D-3D heterostructures, through large-scale molecular dynamics (MD) simulations and frequency-resolved spectral analyses.

In MHPs, the work reveals …

Drag Reduction In Ground Vehicles Using A Model Porous Medium, Abdullah Ikram Nabi

Master’s Theses

This research investigates aerodynamic drag reduction on a 25° Slanted Ahmed Body (SAB) by integrating porous media model rods through combined experimental and computational methods at a Reynolds number of 1.16×10⁴. Two porous media configurations: short rods (6.75% of the model height) and long rods (20.0% of the model height), both featuring cylindrical rods with 80% porosity, were systematically compared against a baseline SAB. In-depth analyses were performed to investigate the wake flow topology, recirculation region characteristics, pressure coefficient distribution, Reynolds stress distributions and drag coefficient. Experimental investigations employed particle image velocimetry for precise flow visualization, while Reynold Averaged Navier-Stokes …

Perceptions, Efficacy, And Adaptation Of Online Learning In Physics And Chemistry Education, Fun Man Fung, Jia Yi Han, Min Xin Pua

Journal of Educational Technology Development and Exchange (JETDE)

The COVID-19 pandemic forced a sudden shift to online learning in Physics and Chemistry in Singapore. As restrictions eased, researchers explored its impact through interviews with instructors and analysis of student data made available through a data lake managed by the National University of Singapore’s Institute for Applied Learning Sciences and Educational Technology. Interviews focused on instructor adaptation and beliefs about online teaching, while the data investigated student perceptions and changes in teaching efficacy pre- and post-pandemic. Analysis of the students’ course feedback indicated that Course Code C005 received more positive feedback from students, particularly towards the instructor’s effectiveness in …

Scalable Parallel-In-Time Integration For Equations Of Motion, Nathan W. Chapman

All Master's Theses

Physical simulations always need to balance accuracy and run-time. This work implements the Parareal Algorithm using graphics processing units across a distributed system to accurately simulate time-dependent physics while attempting to minimize runtime. Data-transfer latency is identified as the primary bottleneck, for which mitigation methods are provided. Benchmarks comparing single-GPU and distributed implementations on a spectrum of coarse and fine discretizations are analyzed.

Investigation Of Colorimetric Trends In Rare-Earth Co-Doped Ypo₄, Barit K. Essman

All Master's Theses

From detectors in scientific instrumentation to medical imaging devices and nuclear monitoring systems to LEDs seen in consumer products, phosphors are utilized in a myriad of applications experienced by both the general public and scientific community alike. For many phosphor applications, emission color and intensity are notably important features to consider. When phosphors are co-doped with rare-earth activators, the ability to predict emission intensity and color output becomes challenging due to competition kinetics and energy transfer between the dopants. During this study, correlation between trends in co-doped phosphor excitation and color output were analyzed to interpret optical behaviors originating from …

Descending An Inclined Plane With A Large Language Model, Justin C. Dunlap, Ryan Sissons, Ralf Widenhorn

Physics Faculty Publications and Presentations

[This paper is part of the Focused Collection in Artificial Intelligence Tools in Physics Teaching and Physics Education Research.] We present a study in which a version of a common conservation of mechanical energy introductory physics problem, an object released on an inclined plane, is given to OpenAI’s GPT-4 large language model (LLM). We investigate how different permutations of object, action verb, and property of the incline impact the responses of the LLM. The problem setup and prompting was left purposefully minimal, requiring the LLM to state multiple assumptions to justify the final answer. We specifically studied how different keywords …

In Vitro Microfluidics System For Mechanobiologic Investigations, Michael A. Daanen

Honors Theses

Mechanobiology is an emerging field that aims to study the relationships between mechanical forces and cellular behavior. Such mechanobiological relationships are especially critical in the cardiovascular system, where endothelial cells lining the vasculature align in response to fluid shear stresses from blood flow (Sinha, 2016). Implanted flow devices, diabetes, chronic hypertension, and various other diseases and pathophysiologies alter vessel geometries and flow dynamics. Such alterations impact fluid shear stress and endothelial cell behavior, leading to microcirculatory dysfunction, vessel leakage, and organ failure (Poredos, 2021; Papadaki, 1999; Leitschuh, 1987). To simulate dysfunctional endothelial cell behavior in vitro and evaluate novel therapeutic …

Theoretical Study Of Phase-Ordering Kinetics With An Anisotropic Surface Tension, Arjun Anand, Ben Vollmayr-Lee

Honors Theses

Coarsening describes the phase-separation dynamics that follows after a temperature quench from a stable to unstable region of the phase diagram in binary systems. Whereas binary systems with an isotropic surface tension have been thoroughly examined and modeled, the case of an anisotropic surface tension lacks the same degree of analysis and development. In this thesis, we demonstrate the self-consistency of the scaling hypothesis with an anisotropic surface tension in the dilute limit. We begin by assuming weak anisotropy in the surface tension and working only to first order in perturbation theory. Following a similar approach laid out in the …

Scp 231 Dictionary + Example Problems [General Physics 1], Daniel Capic

Open Educational Resources

Student-written definitions of key physics concepts that appear in SCP 231. There are also student-written word problems with links to instructor-created video solutions.

Interactions And Applications Of Optical Angular Momentum In Magneto-Optical Material, Seth R. Nelson

Dissertations, Master's Theses and Master's Reports

This dissertation explores the interactions and applications of optical angular momentum within magneto-optical materials. Beginning with a theoretical and experimental analysis of multiple reflection and refraction phenomena within magneto-optical material. We derive and verify the dependence of refractive indices on optical spin angular momentum and magneto-optical magnetization, resulting in nonreciprocal elliptical and linear polarization beam splitting effects and wavevector discretization. We fabricate a magnetless slab waveguide isolator with minimal optical loss. Extending our study to optical orbital angular momentum, we introduce a perturbation to the electronic transition model in bismuth-substituted iron garnets. We demonstrate that this perturbation leads to nonreciprocal …