Physical Sciences and Mathematics Commons^™

Simulating Strongly Coupled Many-Body Systems With Quantum Algorithms, Manqoba Qedindaba Hlatshwayo

Dissertations

The complexity of the nuclear many-body problem is a severe obstacle to finding a general and accurate numerical approach needed to simulate medium-mass and heavy nuclei. Even with the advent of exascale classical computing, the impediment of exponential growth of the Hilbert space renders the problem intractable for most classical calculations. In the last few years, quantum algorithms have become an attractive alternative for practitioners because quantum computers are more efficient in simulating quantum physics than classical computers. While a fully fault-tolerant universal quantum computer will not be realized soon, this dissertation explores quantum algorithms for simulating nuclear physics suitable …

The Luminous Power Of Accretion Disks In Active Galactic Nuclei, Imogen Jade Courtney

Honors Theses

Active Galactic Nuclei (AGN) are the most luminous long-lived objects in the universe. The phenomenon of the immense luminosities we observe for AGN has interested physicists and astronomers for over a century and continues to fascinate scientists today. The work in this thesis aims to provide an introductory exploration of this phenomenon. This thesis uses a simple model of AGN accretion disks that was developed under the standard disk model proposed by Shakura & Sunyev in 1973 under the simplest assumptions. The model accurately demonstrates how physical parameters, such as the temperature, radiative flux, luminosity, and spectra, scale through an …

Studying The Synthesis Of 196Hg At Astrophysically Relevant Energies Through The Measurement Of Capture Reaction Cross-Sections Of (P, Γ) (P, N) And (P, Α) Reactions, Khushi Bhatt

Dissertations

Understanding the origin of all the chemical elements is an important question for the nuclear-astrophysics community. There are many unanswered questions like: What astrophysical events are responsible for the synthesis of what particular chemical elements? How many different elements were made in total? What is the abundance of each synthesized element? etc. Currently, scientists are largely depending upon theory and simulations to define nuclear and astrophysical reaction. This makes it critical to have accurate experimental nuclear physics data to input in astrophysical theoretical models. However, out of more than 20000 reactions involved in these calculations, only a very few are …

Time-Dependent Photoionization Modeling Of Warm Absorbers In Active Galactic Nuclei, Dev Raj Sadaula

Dissertations

Warm absorber spectra are bound-bound and bound-free absorption features, seen in the X-ray and UV spectra from many active galactic nuclei (AGN). The widths and centroid energies of these features indicate they occur in outflowing gas moving with hundreds to thousands of km/s. Depending upon the energy and momentum of the outflow, it can affect the gas within the host galaxy. Thus, warm absorbers’ mass and energy budgets are of great interest. Estimates for these properties depend on models that connect the absorption features' observed strengths with the density, composition, and ionization state of the absorbing gas. Such models assume …

Probing The Equation Of State Of Neutron Stars With Heavy Ion Collisions, Om Bhadra Khanal

Dissertations

The equation of state (EOS) is a fundamental property of nuclear matter, important for studying the structure of systems as diverse as the atomic nucleus and the neutron star. Nuclear reactions, especially heavy-ion collisions in the laboratories, can produce the nuclear matter similar to those contained in neutron stars. The density and the momentum dependence of the EOS of asymmetric nuclear matter, especially the symmetry energy term, is widely unconstrained. Finding appropriate constrains, especially at higher densities of the nuclear matter, requires the development of new devices, new experimental measurements as well as advances in theoretical understanding of nuclear collisions …

Study Of Deexcitation Intensities To The K-Shell In Iron 55, Eric Helgemo

Honors Theses

55Fe radioactive sources are used for x-ray calibration due to the long half-lives of 2.73 years and the optimal energies of the peaks. The source used in the experiment was generated using Western Michigan University’s Tandem Van de Graff accelerator to produce a 6 MeV proton beam which induced a 55Mn(p, n)55Fe reaction on a 10 μm 55Mn target. The emissions from this target were then measured using a silicon lithium drift x-ray detector to determine the number of instances of deexcitation through kα and kβ modes. The preliminary data discussed showed a lower relative deexcitation rate of 6.67 between …

Novel Low Temperature Properties Of Filled And Unfilled Single Crystal Irsb3, Matthew Cook

Dissertations

The skutterudite family of materials has garnered a lot of attention in the condensed matter community and it persists to be an important system for exploring the fundamental physics of solids. The initial interest into compounds with this common structure was due to their promising thermoelectric properties giving the possibility of efficient energy harvesting. Since, there has been a huge effort to systematically synthesize new filled skutterudite compounds, as nearly every type of strongly correlated behavior has been found within this family. As the field of topological materials has gained momentum, these materials have also been given a renewed interest …

Enhancement Of Critical Current In High-Temperature Superconductors By Ion Beam Irradiation Induced Defects, Prashanta Mani Niraula

Dissertations

Particle irradiation is used to induce defects in high-temperature superconducting Y₁Ba₂Cu₃O_7-x (YBCO) coated conductors, containing predominantly c-axis oriented barium zirconate (BZO) nanorods as pre-existing vortex pinning defects. Samples are irradiated with 50.0 MeV Cu ions with doses of 2.5 x 10¹², 2.0 x 10¹², 1.5 x 10¹², 1.0 x 10¹², 0.75 x 10¹², 0.5 x 10¹², 0.05 x 10¹² ions/cm². The dose of 0.5 x 10¹² ions/cm² is found to be the optimal dose with a …

Issues And Proposed Solutions To Team Based Assessment In University Physics Labs, Manqoba Q. Hlatshwayo

STEM Instructional Graduate Teaching Assistant Posters

Many education experts considers peer-to-peer education as the most effective way for students to learn (Peersdom, 2014). Western Michigan University (WMU) physics laboratories embraces this philosophy and has designed the assessment to be based on the team report. The assumption is that every team member contributed (not necessarily equally) to the work submitted by the team hence every team member should receive the same grade. This is a ubiquitous assessment philosophy in education, and some forms of additional individual assessment in team projects are strongly discouraged (David Boud et al, 1999).

There is no doubt on the effectiveness of peer-to-peer …

Improving Lab Experience For Students In Phys2080, Khushi Bhatt

STEM Instructional Graduate Teaching Assistant Posters

University Physics II (PHYS 2080) deals with providing hands-on experience with the experiments of electricity and magnetism. It aids students to develop computational thinking in physics through analysis of experimental and theoretical data using python programming language.

In Fall-2019, I taught the newly designed PHYS2080 class for the first time as per the requirements. During Spring-2020, I implemented some subtle changes using the skills that I gained through various teaching training. These changes are described in Methodology section. Data clearly shows improvement that was observed without lowering the expectations or changing the curriculum of the class.

Embedded Gold Nanoparticles For Metal Enhanced Photoluminescence, Hasna Alali

Dissertations

Noble metal nanoparticles (MNPs) have attracted great attention in electronics, solar cells and catalysis. Their unique optical properties and biocompatibility makes them useful in biological applications like imaging, drug delivery, therapy and diagnostic. At the surface of MNPs the collective oscillation of free electrons resonates with a particular wavelength of incident light, generating the Localized Surface Plasmons Resonance (LSPR). LSPR results in absorption and scattering of incident light. Scattering results in reflecting photons and absorption leads to enhanced photoluminescence and quenching of fluorophores, if the fluorophore is in the vicinity of MNPs.

Most of the studies in this regard have …

Investigation Of Finite Temperature And Continuum Effects On Nuclear Excitations, Herlik Wibowo

Dissertations

The low-energy nuclear response at finite-temperature significantly affects the radiative neutron capture reaction rates of the r-process nucleosynthesis. In order to address this topic, the first part of this study focuses on the response of compound nuclei or nuclei at finite temperature. The thermal nuclear response satisfies the Bethe-Salpeter equation (BSE) with the static and dynamical kernels of different origins. While the origin of the static kernel is the nearly instantaneous nucleon-meson interaction, the dynamical kernel is induced by the coupling between nucleons and phonons. The presence of singularities in the dynamical kernel makes the BSE unsolvable, however, a time …

Embedded Silver Nanoparticles For Metal Enhanced Photoluminescence, Shahid Iqbal

Dissertations

Imaging of biologically significant molecules using plasmons of Metal Nanoparticles (MNPs) is gaining attention in the research community. Localized Surface Plasmon Resonance (LSPR) is the coherent oscillation of conduction electrons of MNPs. The biologically significant molecule is labeled with the fluorophore molecule to get the image. This approach is widely used in clinical practices, however, low intensity light emission from the labeled molecule makes it difficult to image the biologically significant material. One way to improve the weak intensities of fluorophore is to enhance the brightness using a process called Metal Enhanced Photoluminescence (MEP). This phenomenon occurs in the close …

Simultaneous X-Ray Emission Accompanying Two Electron Capture For Fluorine On Gas Targets, David S. La Mantia

Dissertations

The collision between a charged ion and an atom resulting in the capture of two electrons, simultaneous with the emission of a single photon is referred to as radiative double electron capture (RDEC). For ion-atom collisions, this process can be considered the inverse of double photoionization. The study of either process, where just two electrons are involved without influence from neighboring electrons, promises new insight into electron correlation and the role it plays in quantum mechanics. Such a study for photoionization has not yet been done experimentally for two-electron ions because the only target system for which two electrons are …

Synthesis And Characterization Of Ion-Implanted Gold Nanoparticles, Nurlathifah Fnu

Masters Theses

Gold negative ions of 70 keV energy were implanted within the quartz substrates at room temperature at seven different fluences starting from 2 x 10¹⁶ particles/cm² to 8 x 10¹⁶ particles/cm² with the increment of 1 x 10¹⁶. Prior to the implantation, Stopping and Range of Ions in Matter (SRIM) calculations were carried to obtain the Bragg peak below the surface of quartz. Rutherford Backscattering Spectrometry (RBS) was carried out using 2.0 MeV He⁺⁺ ions to measure depth and implanted fluence of gold, and learn how they varied with fluence. Backscattered He particles …

Fostering Computational Thinking In An Introductory Physics Lab, Diana Sachmpazidi

STEM Instructional Graduate Teaching Assistant Posters

•Thinking computationally means conceptualizing a problem and formulating it in a way that a computer can solve it (Wing, 2010). •Computational Thinking (CT) is the third pillar of the scientific method along with theory and experimentation and is a fundamental skill that K-12 students and undergraduates should be equipped with (Wing, 2016; 2006). •Research on CT has only been active the last 10 years and most studies are still at the stage of ideas (Kalelioglu et al., 2016). •The integration of CT aspects in instruction is a widely expanding phenomenon in physics classrooms in the context of higher education, and …

Investigation Of Structural, Optical And Electronic Properties Of Modified Methylammonium Lead Iodide Perovskites, Rasanjali Jayathissa

Dissertations

Owing to their high-power conversion efficiency (PCE), easy processability, and low fabrication cost, organic lead halide perovskites (OLHP) are emerging as a most promising photovoltaic technology. However, toxicity of lead (Pb) is a major concern for further development. Therefore, it is essential to explore nontoxic metals to replace lead in these materials. In the current research work, nontoxic Mn²⁺, Na⁺ and Ba²⁺ are doped at 1, 5 and 10% mole concentrations to partially substitute Pb²⁺ in methyl ammonium lead iodide (CH₃NH₃PbI₃ or MAPbI₃) perovskite systems, and the effects …

Sensitivity Of The Theoretical Electron Capture Shape And Comparisons To Experiment, Katrina E. Koehler

Dissertations

The direct neutrino mass is a fundamental physics quantity with far-reaching implications for the physics community. Current experimental limits put the direct neutrino mass at less than 2 eV. The neutrino mass can be explored through an end-point measurement of tritium beta decay, which is currently underway in the KArlsruhe TRItium Neutrino experiment (KATRIN). KATRIN has a lower limit of 0.2 eV, at which point there will be either a mass measurement or another upper bound. In either case, an alternative experiment with different systematics is needed to verify the results and/or push the upper bound lower. The end point …

Radiative Double Electron Capture By Ions In Collisions With Gas Targets, Charles Taylor

Honors Theses

Radiative double electron capture (RDEC) is a two-step quantum process where two electrons are captured from the target gas to the projectile ion beam with a simultaneous emission of a single photon. The projectile ion beam was obtained from the tandem Van de Graaff accelerator at Western Michigan University. The projectile beam used is fully and partially ionized fluorine 9+, and 8+ in collision with highly pure nitrogen gas. The objective of the research is to observe RDEC from x ray detection using time to amplitude converters (TACs) that look for coincidences between x rays and particles. The signal from …

Radiative Double Electron Capture (Rdec) By Fully-Stripped Fluorine Ions In Collisions With Nitrogen, Nuwan Sisira Kumara

Dissertations

Radiative double electron capture (RDEC) by highly-stripped ions in collisions with atomic targets is a fundamental process that can be used to study electron-electron correlation, the interaction between two electrons, in the vicinity of the Coulomb field of a bare ion. In this process two electrons from the target are captured to bound states of the projectile with the simultaneous emission of a single photon. RDEC is closely related to the well-known one-step atomic process of radiative electron capture (REC), in which a target electron is captured to the projectile and a photon is simultaneously emitted. REC and RDEC can …

Department Of Physics Newsletter, Summer 2018, Department Of Physics

Physics Newsletter

• Message from Dr. Kirk Korista, Department Chair
• 2017 Alumni Achievement Award, Physics
• 2017 Solar Eclipse
• Department of Physics Award Ceremony

A 3d Simulation Of Leukocyte Adhesion In Blood Flow, Tai-Hsien Wu

Dissertations

It has been widely acknowledged that further understanding about the dynamics between blood cells and blood flow can help us gain more knowledge about the causes of diseases and discover more effective treatments. Examples of such dynamics include red blood cell (RBC, or erythrocyte) aggregation, white blood cell (WBC, or leukocyte) margination, and WBC extravasation. WBC extravasation is an important multiple-step process in the inflammatory response and therefore has drawn considerable attention over the past two decades. In this multiple-step process, a WBC undergoes at least four steps, including capture, rolling, firm adhesion, and transmigration, and each step is influenced …

The Proton Veto Project At Wmu/Msu, Justin Swaim

Honors Theses

The Proton Veto Wall (VW) is a charged particle detector designed and built at Western Michigan University for use at the National Superconducting Cyclotron Laboratory at Michigan State University. The VW assists the Large Area Neutron Array (LANA) with discriminating between charged particles detected via proton recoil in the scintillating material and charged particles detected from heavy ion collisions produced in the laboratory. Twenty five Eljen-200 plastic organic scintillators are arranged in a vertical position with photomultiplier tubes (PMTs) mounted to either end. The detector sits directly in front of LANA on a large stand that was assembled using T-slotted …

Dielectronic Recombination Calculations For Silicon-Like Ions And The S2+ Orion Nebula Abundance Conundrum, Jagjit Kaur

Dissertations

Modern astronomical spectroscopy and imaging data are of an unprecedented quality, and span the full electromagnetic spectrum. To take full advantage of these data and successfully model the physical conditions in and elemental abundances of astrophysical plasmas, an accurate and complete description of relevant atomic processes occurring in a wide range of cosmic environments is required. The primary focus of this project is to investigate one of the atomic processes, dielectronic recombination (DR), for the entire silicon-like isoelectronic sequence. Dielectronic recombination is generally the most important contribution to the total recombination rate of atomic ions. This study will serve as …

Department Of Physics Newsletter, Summer 2017, College Of Arts And Sciences

Physics Newsletter

• Message from Dr. Kirk Korista, Department Chair
• Science Olympiad draws 400 hundred students to WMU
• 2016 Alumni Achievement Award, Physics
• Department of Physics Award Ceremony
• Faces of Physics

Time-Dependent Photoionization Of Gaseous Nebulae, Ehab Elsayed Elhoussieny Ahmed

Dissertations

We study time-dependent photoionization of gaseous nebulae, i.e. the physical conditions and spectra of astronomical plasmas photoionized by a time-dependent source of ionizing radiation. Our study proceeds in two chief steps: First, we start with a simplified model of plasmas of pure H. Second, we develop a more realistic model of plasmas composed of a mixture of chemical elements. For the first step, we wrote a time-dependent photoionization code (TDP) that solves the coupled system of equations for ionization, energy balance, and radiation transfer in their full time-dependent forms For the second step, we developed a more realistic code (TDXSTAR) …

Type 1a Supernova Models And Galactic Chemical Evolution, Spencer Henning

Honors Theses

Multiple models of type Ia supernovae are discussed, as well as the properties of white dwarf formation, electron degeneracy pressure, nucleosynthesis, and galactic chemical evolution (GCE). A GCE computer model is used to produce nuclear abundance data corresponding to Chandra (W7) and sub-Chandra (WDD2) type Ia supernovae models for Ca, Sc, Ti, V, Cr, and Mn nuclei. Overall, a trend was found indicating that the WDD2 model had greater [x/Fe] abundance values than the W7 model at the end time of the model. Additionally, each model fit within total observed data, but observed data filtered to highlight white dwarf stars …

The Quantum Dancing Of Hot Atomic Nuclei: A New Theoretical Approach, Herlik Wibowo

Research and Creative Activities Poster Day

We study the nuclear excitation spectra in the two energy domains: the low energy region (below 10 MeV) and giant resonance (GR) region (10-30 MeV). In the low energy region, the experimentally discovered upbend of the radiative dipole strength function is very important as it has an impact on the rapid neutron capture cross sections, which are used, in particular, for the r-process nucleosynthesis studies.

Thermal continuum quasiparticle random-phase approximation (TCQRPA) is one of the models which attempts to explain this phenomenon. The deficiency of TCQRPA is the absence of quasiparticle vibration coupling (QVC) mechanism, which is already included in …

Crystallography And Magnetism Of Magnetocalorically Important Ni-Mn-X Based Heusler Alloys, Amila S. B. Madiligama

Dissertations

Ni-Mn-X Heusler alloys, demonstrating strong coupling between crystalline structure and magnetic state, were studied. They undergo field-induced, first-order transformations from a low symmetry martensite to a high-symmetry austenitic phase around room temperature. The substantial difference between the entropies of the two phases results in a large adiabatic temperature change, called “Giant Magnetocaloric Effect (GMCE)”. Consequently, these alloys are promising refrigerants for near-room temperature cooling systems. This magnetic cooling is an energy-efficient and eco-friendly technology.

Crystalline structures and magnetic states of these alloys, which determine their magnetocaloric performances, highly depend on their composition. To examine new paths to optimize their magnetocaloric …

An R-Matrix, Quantum Defect Theory Approach To The Photoionization Of Molecular Nitrogen, Gaetan L. Vangyseghem

Dissertations

No abstract provided.