Physical Sciences and Mathematics Commons^™

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM Month

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …

Predictive Models Of Polymer Composites: A Thesis, Navid Afrasiabian

Electronic Thesis and Dissertation Repository

Predictive models are a powerful tool to understand and improve physical systems. Predictive models not only can be used to improve current materials, but they also gain fundamental understanding of the underlying processes. There are numerous theoretical and numerical models introduced in the field of polymer composites and nanocomposites. Different methods best describe a system at a specific time and length scale. In this thesis, I utilize Coarse-grained Molecular Dynamics (CGMD), Multi-PhaseField (MPF), and Lattice-Boltzmann (LB) methods to study different aspect of polymer composites and nanocomposites.

Starting at the nanoscale, we study the dispersion and orientation patterns of nanorod-polymer systems …

Revolutionizing Wild Silk Fibers: Ultrasound Enhances Structure, Properties, And Regenerability Of Protein Biomaterials In Ionic Liquids., Xincheng Zhuang, Haomiao Zhu, Fang Wang, Xiao Hu

College of Science & Mathematics Departmental Research

Ultrasound-assisted regulation of biomaterial properties has attracted increasing attention due to the unique reaction conditions induced by ultrasound cavitation. In this study, we explored the fabrication of wild tussah silk nanofiber membranes via ultrasound spray spinning from an ionic liquid system, characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), atomic force microscopy (AFM), water contact angle, cytocompatibility tests, and enzymatic degradation studies. We investigated the effects of ultrasound propagation in an ionic liquid on the morphology, structure, thermal and mechanical properties, surface hydrophilicity, biocompatibility, and biodegradability …

63rd Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 63rd annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in the Copper Conference Center, Copper Mountain, Colorado, August 4-8, 2024.

A Review Of Stable, Traversable Wormholes In F(R) Gravity Theories, Ramesh Radhakrishnan, Patrick Brown, Jacob Matulevich, Eric Davis, Delaram Mirfendereski, Gerald Cleaver

Physics and Astronomy Faculty Publications and Presentations

It has been proven that in standard Einstein gravity, exotic matter (i.e., matter violating the pointwise and averaged Weak and Null Energy Conditions) is required to stabilize traversable wormholes. Quantum field theory permits these violations due to the quantum coherent effects found in any quantum field. Even reasonable classical scalar fields violate the energy conditions. In the case of the Casimir effect and squeezed vacuum states, these violations have been experimentally proven. It is advantageous to investigate methods to minimize the use of exotic matter. One such area of interest is extended theories of Einstein gravity. It has been claimed …

Maximizing Legged Accelerations: A Matter Of Force, Time, And Gravity, Lance Brooks

Applied Physiology and Wellness Theses and Dissertations

Sprint running accelerations require runners to apply surface forces that: support body weight by pushing downward, accelerate the body horizontally by pushing backward, and align the direction of the push with the body’s mass center to maintain balance and posture, which imposes an upper limit on the average forward acceleration force equal to the average gravitational force (1.0 G) acting on the runner. This expectation arises from the mechanical constraints imposed by the need to generate sufficient vertical force to support body weight against gravity while simultaneously producing horizontal force to accelerate forward and aligning the push through the center …

Constraints On Solar Axions Using The Profile Likelihood Ratio Method With The Supercdms Experiments, Shilun Liu

Physics Theses and Dissertations

Dark matter plays an essential role in understanding modern physics and particles beyond the Standard Model. Evidence suggests that dark matter accounts for approximately 85% of the universe’s matter, and 26.8% of its mass-energy composition. Key candidates for dark matter include unidentified subatomic particles like Weakly Interacting Massive Particles (WIMPs) and axions. The Super Cryogenic Dark Matter Search (SuperCDMS) employs direct detection methods to identify these elusive particles using cryogenic technologies. Su- perCDMS Soudan is the latest completed CDMS experiment in Minnesota, in preparation for the next phase experiments of SuperCDMS SNOLAB in Sudbury, Canada. At SNOLAB, the Cryogenic Underground …

Madelung Mechanics And Superoscillations, Mordecai Waegell

Mathematics, Physics, and Computer Science Faculty Articles and Research

In single-particle Madelung mechanics, the single-particle quantum state Ψ(⃗x, t) = R(⃗x, t)eiS(⃗x,t)/h is interpreted as comprising an entire conserved fluid of classical point particles, with local density R(⃗x, t)2 and local momentum ⃗∇S(⃗x, t) (where R and S are real). The Schrödinger equation gives rise to the continuity equation for the fluid, and the Hamilton–Jacobi equation for particles of the fluid, which includes an additional density-dependent quantum potential energy term Q(⃗x, t) = − ¯h2 2m ⃗∇R(⃗x,t) R(⃗x,t) , which is all that makes the fluid behavior nonclassical. In particular, the quantum potential can become negative and create a …

Three-Wave Mixing Experiments In Indium–Tin–Oxide Thin-Films With No Phase Matching, Kyle Wynne, Marjan Bazian, Mark C. Harrison

Engineering Faculty Articles and Research

One challenge of using nonlinear optical phenomena for practical applications is the need to perform phase-matching. Recently, epsilon-near-zero materials have been shown to demonstrate strong optical nonlinearities, in addition to their other unique properties. As suggested by their name, the permittivity of the material is close to zero for a certain wavelength range. We demonstrate that this small permittivity allows for efficient three-wave mixing interactions to take place in indium–tin–oxide thin films without the need for phase matching the pump and signal beams. The efficiency of the second-order nonlinear interactions is characterized, and cascaded three-wave mixing is demonstrated.

On Weak Solutions And The Navier-Stokes Equations, Aryan Prabhudesai

Mathematical Sciences Undergraduate Honors Theses

In this paper, I will discuss a partial differential equation that has solutions that are discontinuous. This example motivates the need for distribution theory, which will provide an interpretation of what it means for a discontinuous function to be a “solution” to a PDE. Then I will give a detailed foundation of distributions, including the definition of the derivative of a distribution. Then I will introduce and give background on the Navier-Stokes equations. Following that, I will explain the Millennium Problem concerning global regularity for the Navier-Stokes equations and share mathematical results regarding weak solutions. Finally, I will go over …

Instantons In Φ4 Theories: Transseries, Virial Theorems, And Numerical Aspects, Ludovico T. Giorgini, Ulrich D. Jentschura, Enrico M. Malatesta, Tommaso Rizzo, Jean Zinn-Justin

Physics Faculty Research & Creative Works

We discuss numerical aspects of instantons in two- and three-dimensional φ4 theories with an internal O(N) symmetry group, the so-called N-vector model. By combining asymptotic transseries expansions for large arguments with convergence acceleration techniques, we obtain high-precision values for certain integrals of the instanton that naturally occur in loop corrections around instanton configurations. Knowledge of these numerical properties is necessary in order to evaluate corrections to the large-order factorial growth of perturbation theory in φ4 theories. The results contribute to the understanding of the mathematical structures underlying the instanton configurations.

Perturbative Versus Non-Perturbative Renormalization, S. Hariharakrishnan, Ulrich D. Jentschura, I. G. Marian, K. Szabo, I. Nandori

Physics Faculty Research & Creative Works

Approximated functional renormalization group (FRG) equations lead to regulator-dependent β-functions, in analogy to the scheme-dependence of the perturbative renormalization group (pRG) approach. A scheme transformation redefines the couplings to relate the β-functions of the FRG method with an arbitrary regulator function to the pRG ones obtained in a given scheme. Here, we consider a periodic sine-Gordon scalar field theory in d = 2 dimensions and show that the relation of the FRG and pRG approaches is intricate. Although both the FRG and the pRG methods are known to be sufficient to obtain the critical frequency β c 2 = 8 …

Doubly Differential Cross Sections For Ionization In Proton Collisions With Atomic Hydrogen: Energy And Angular Distribution Of Emitted Electrons, C. T. Plowman, K. H. Spicer, N. W. Antonio, M. S. Schöffler, Michael Schulz, I. Bray, A. S. Kadyrov

Physics Faculty Research & Creative Works

We use the two-center wave-packet convergent close-coupling approach to ion-atom collisions to calculate the energy and angular distribution of electrons emitted in proton collisions with atomic hydrogen. Results are provided across a wide range of intermediate energies where many competing reaction channels make calculations challenging. The present data consistently agree with the available experimental measurements and improve upon previously available results based on perturbative and classical methods. Furthermore, we extend the range of electron angles and energies over which theoretical data are available for the doubly differential cross section for ionization. This provides strong evidence that at the level of …

Methods For Improving Low Frequency Selection And Electrode Firing Order In Cochlear Implants, James H. Keen Jr.

University of New Orleans Theses and Dissertations

The Advanced Bionics cochlear implant devices allocate static frequency bins to electrode channels based on the natural tonotopic organization of the cochlea. These frequency bins are wide and limited, especially in the lower range. Considering that the fundamental tones of the human voice and the primary melodic tones in music are in this lower range, it is important to have accurate representation of this frequency content. Here, adjustments to the frequency bin allocation algorithm used in the crowdsourced CI Hackathon code are made to allow a more accurate representation of the original signal. First, the frequency bins allocated to each …

Investigation Of Optically Pumped Gesn Quantum Well Lasers, Grey Steven Abernathy

Graduate Theses and Dissertations

Silicon photonic integrated circuits enable the capability of producing on-chip processing of photonic signals, including both emission and detection. Emission materials, however, have been limited for monolithic integration due to high processing temperatures, indirect bandgap materials, and material integration complications. The (Si)GeSn material system has recently attracted attention due to the bandgap transition from the Si and Ge, naturally indirect bandgap, to direct bandgap with sufficient Sn incorporation. Additionally, the low growth temperature (CMOS compatible; <400 >°C) of (Si)GeSn materials can enable the monolithic integration of the highly desired mid-infrared light emission on the Si Photonic platform. This dissertation first discusses …

Understanding And Control Of Frustration And Topological Defects In Ferroic Matter, Suyash Rijal

Graduate Theses and Dissertations

Ferroic matter are of great importance as they provide a platform to extend the understanding of many-body physics and also for their amazing functional properties relevant for technological advancements. The work in this dissertation is dedicated to two of such ferroic materials. First is CrGeTe3 (CGT), a two dimensional (2D) magnet discovered in 2017. The discovery of two-dimensional magnetism has invigorated the research community as their low dimensionality offers a unique avenue to understand and investigate the origin of magnetism in these atomically thin systems and harvest diverse application such as information processing, storage and transfer using their magnetic spins. …

Numerically Efficient Coherent Mode Representations For Partially Coherent Beams With Separable Phases, Milo W. Hyde, Carolina Rickenstorff

Faculty Publications

We present a method to numerically compute the coherent mode representations (CMRs) for partially coherent beams with separable phases. This special class of random light field has the ability to self-focus and is resistant to turbulence-induced degradation, making it potentially useful in applications such as optical communications. We validate our method by generating (in simulation) two such sources from the literature using their computed CMRs. Lastly, we conclude with a summary of our approach and a discussion of potential applications.

3d-Magnetometer Arrays In Physics Experiments, Shaun G. Vavra

Masters Theses

This study presents the design and experimental evaluation of a magnetometer array utilizing LIS3MDL chips integrated with an Arduino microcontroller. Magnetometer arrays find crucial applications in various fields, including physics research, geophysics, and navigation systems. The goal of this research is to create an affordable and versatile magnetometer array for scientific investigations and practical applications. The paper begins by outlining the hardware and software components of the array. The LIS3MDL chips, known for their high sensitivity and low power consumption, are employed as the core sensing elements. The Arduino microcontroller is utilized for data acquisition and processing. The integration of …

Md Simulations Of Collision Effects For A Strongly Coupled Plasma, Jawon Jo

All Graduate Theses and Dissertations, Fall 2023 to Present

Studying strongly coupled plasmas can be effectively accomplished using molecular dynamics (MD) simulations. We have developed an advanced MD simulation code that can analyze plasmas with various coupling parameters. This code employs a spherically symmetric cut-off Coulomb force verified through convergence tests by modulating the cut-off and minimum force ranges. Additionally, it incorporates a new algorithm for optimizing the initial positions of particles at a given temperature. This method maintains the temperature constant and the velocity distribution unchanged. As a result, we eliminate the unphysical initial rises and oscillations in temperature that a random distribution of positions causes. The code …

Dispersive Shock Waves In A One-Dimensional Droplet-Bearing Environment, Sathyanarayanan Chandramouli, S. I. Mistakidis, G. C. Katsimiga, P. G. Kevrekidis

Physics Faculty Research & Creative Works

We demonstrate the controllable generation of distinct types of dispersive shock waves emerging in a quantum droplet bearing environment with the aid of steplike initial conditions. Dispersive regularization of the ensuing hydrodynamic singularities occurs due to the competition between mean-field repulsion and attractive quantum fluctuations. This interplay delineates the dominance of defocusing (hyperbolic) and focusing (elliptic) hydrodynamic phenomena being designated by the real and the imaginary speed of sound, respectively. Specifically, the symmetries of the extended Gross-Pitaevskii model led to a three-parameter family, encompassing two densities and a relative velocity of the underlying Riemann problem utilized herein. Surprisingly, dispersive shock …

Search For Physics Beyond The Standard Model In Top Quark Production With Additional Leptons In The Context Of Effective Field Theory, Furong Yan

Dissertations and Doctoral Documents from University of Nebraska-Lincoln, 2023–

The dissertation presents a search for new physics impacting top quark productions within the framework of effective field theory (EFT). Potential new physics effects are parameterized in terms of 26 dimension-six EFT operators into the event yields of six distinct top production processes in the detector level. The analysis targets multilepton final states consisting of two leptons of the same charge, three leptons and four leptons. The events are further categorized and binned in terms of kinematic distributions in order to gain sensitivity to the new physics effects. A likelihood function is formulated based on the predicted distribution in each …

Investigation Of Seasonal Trends And Source Apportionment Of Particulate Matter (Pm2.5) In El Paso-Juarez Airshed, Fatema Tuz Zohora

Open Access Theses & Dissertations

Using the data from Texas Commission on Environmental Quality (TCEQ) for the El Paso city throughout the years from 2021 to 2024 Particulate Matter (PM2.5) was measured to examine the seasonal distribution and sources. This study aims to understand the seasonal variability of PM2.5 concentrations, identify the significant impact of wildfire events on this and source apportionment.The analysis begins with a comprehensive examination of PM2.5 data from TCEQ highlighting the seasonal pattern, it was found that fine particulate matter was more prevalent in winter and tends to be down in spring, and in summer it is relatively lower, subsequently in …

Electroweak Interactions On The Deuteron, Jose Luis Bonilla

Doctoral Dissertations

This research explores the intricacies of Electroweak Interactions on the Deuteron, with a particular focus on muon capture and the hyperfine shift in atomic and muonic deuterium. These processes are phenomena of significant importance in nuclear physics. Understanding these interactions is crucial for illuminating fundamental aspects of nuclear structure and providing insight into the fundamental forces and interactions governing atomic and nuclear systems, as well as related processes such as proton-proton fusion or other astrophysical reactions, which are phenomena that cannot be easily reproduced in a laboratory and require a theoretical treatment to predict observables. Through this research, we systematically …

Determining Heterogeneous Growth Rates Of Brucite On Magnesia Using Multiharmonic Qcm-D And X-Ray Scattering Methods, Pedro Josue Hernandez Penagos

Open Access Theses & Dissertations

The Earth’s temperature has increased in the last six decades mainly due to the emissions of greenhouse gases, including carbon dioxide (CO2). Mineral looping using magnesium oxide (MgO) is a promising approach for direct air capture (DAC) of CO2 from the atmosphere at the GtCO2/yr scale. The presence of humidity during the carbonation process will lead to a reaction between the MgO and water resulting in magnesium hydroxide formation, Mg(OH)2, growing over the MgO surface forming a shell-like structure. The influence of temperature and relative humidity variation on heterogeneous nucleation and crystal growth kinetics of Mg(OH)2 on MgO is not …

Quantum Circuit Optimization Leveraging Multi-Qubit Exchange Interactions In Spin Qubits, Miguel Gonzalo Rodriguez

Open Access Theses & Dissertations

This thesis looks into how multi-qubit exchange interactions can be used to improve quantumcircuits in semiconductor quantum devices. Pairwise interactions between qubits are a common tenet of traditional quantum computing paradigms, although they can impose complexity and depth constraints on circuits. In order to improve the efficiency and scalability of quantum circuits, this research explores the theoretical underpinnings and practical uses of multi-qubit interactions. A thorough theoretical framework is formulated, outlining the mathematical equivalence of a unitary matrix representing interactions between multiple qubits. We obtain the timeevolution operator by analyzing the Hamiltonian of three spin-1/2 particles. A number of quantum …

Capillary Phenomena In Flow Down Fibers: Beads, Bridges, Sheets, And Threads, Chase Tyler Gabbard

All Dissertations

Capillary phenomena are ubiquitous in everyday life with surface tension responsible for shaping liquids and deforming slender structures on length scales smaller than the capillary length, as seen in the formation of drops from a leaky faucet and in the coalescence of wet hair, respectively. Recently, thin film flow down fibers have received significant attention for their ability to produce bead-on-fiber patterns with associated high surface area-to-volume ratios that optimize retention times in heat and mass transfer applications. The presence of a base flow gives rise to complex dynamics including absolute and convective instabilities. The parallelization of these processes through …

Synthesis And Characterization Of A Zirconium (Zr) Thin Film On Si(100) Via Pulsed Laser Deposition, Zikrulloh Khuzhakulov

Masters Theses & Specialist Projects

This study investigates the synthesis and characterization of zirconium (Zr) thin films deposited on Si(100) substrates using pulsed laser deposition (PLD). The effects of two laser wavelengths (1064 nm and 532 nm), various substrate temperatures (25 °C, 300 °C, and 500 °C), and different laser fluences (0.25, 0.5, 1.0 J/cm²) on the properties of the Zr films were examined. Results indicated that smoother films were achieved with the 1064 nm wavelength, while surface roughness increased with higher fluences. Optimal crystalline films were obtained at a substrate temperature of 300 °C for both wavelengths. X-ray diffraction (XRD), scanning electron microscopy (SEM), …

Pion, Kaon, And Proton Production In Jet-Hadron Correlations From Pb-Pb Collisions At $\Sqrt{S_{Nn}}$=5.02 Tev Using The Alice Detector, Patrick J. Steffanic

Doctoral Dissertations

Interactions between hard probes and the quark-gluon plasma (QGP) are a rich probe of the dynamics of the QGP. In this thesis, we study the production of pions, kaons and protons from jet-hadron correlations in 0-10% and 30-50% central Pb-Pb collisions at √s_NN = 5.02 TeV with the ALICE detector at the LHC. We focus our studies on low momentum jets with 20 GeV/c < p_T^jet < 40 GeV/c using associated hadrons with 1 GeV/c < p_T^assoc. < 10 GeV/c. The yields of associate pions, kaons and protons were measured in the near-side and away-side regions of the jet-hadron correlation function, and the baryon to meson and strange to non-strange meson ratios were computed. This is the first measurement of the strange to non-strange meson ratio for hadrons associated with a jet. We find the baryon to meson ratio for associated hadrons in Pb-Pb collisions to be within uncertainty of the ratio for inclusive charged hadrons in proton-proton collisions. The strange to non-strange meson ratio for associated hadrons in Pb-Pb collisions shows strong enhancement at intermediate p_T^assoc. relative to the ratio for inclusive charged hadrons in proton-proton collisions, with a hint of enhancement over the ratio for inclusive charged hadrons in Pb-Pb collisions. We find that …

Prompt Vs Local Redeposition: Model Refinement And Experimental Design For Understanding High-Z Net Erosion In Magnetic Confinement Fusion, Davis C. Easley

Doctoral Dissertations

The economic and engineering success of magnetic confinement fusion reactors significantly depends upon the optimization of plasma facing component (PFC) design. For high-Z PFCs, the critical engineering condition is minimal net erosion (i.e. gross erosion – redeposition). Here, we present a high-Z net erosion model discriminating three primary redeposition mechanisms: prompt (geometric-driven), local (sheath-driven), and far (scrape-off-layer-driven). Using these distinctions, we show modeling for high-Z net erosion in magnetic-confinement fusion over a matrix of key plasma parameters. With Sobol’ methods we assess the sensitivity of each mechanism and show that prompt-vs-local trade-off critically explains underprediction in redeposition losses of up …

Studies Of Exotic Electronic, Optical, And Electrochemical Properties In Nanoparticle Assembly And Graphene, Jay Min Lim

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is well known that exotic properties and phenomena emerge as structural dimensions shrink to nanoscales. We self-assembled one-dimensional chains of gold nanoparticles in solution and quantified the growth process by monitoring the redshift of localized surface plasmon resonance (LSPR). Curiously, the redshift stopped while the chains continued to rearrange as manifested by gradual reduction in the LSPR peak. Using electromagnetic simulations, we quantitatively explained the phenomena as a rapid “addition-polymerization” followed by a sharp transition to “condensation-process.” Next, recognizing the significant electric field enhancement in the interparticle gap, a photoluminescent-active Eu³⁺ ion was used to probe Surface-Enhanced Photoluminescence …