Physics Commons^™

Connecting The Nano And The Macro: A Study Of Pore Structure In Carbon Black Nanocomposites, Evangalene Dreyer

Student Scholars Day Posters

Positronium Annihilation Lifetime Spectroscopy (or PALS) uses the lifetime of the bound state of the electron and its antiparticle, the positron (positronium), to determine the pore size, a nanoscale property. By measuring the evolution of pore size as a function of temperature one can determine the phase. Additionally, a macroscopic property called Young’s Modulus affects how much the sample is capable of stretching when a known force is applied. Thus, by measuring the pore size and Young’s Modulus, it is possible to gain a better understanding of how alterations at the microscopic level (pore size) affect the macroscopic properties (Young’s …

Experimental Determination Of The (0/−) Level For Mg Acceptors In Β-Ga2O3 Crystals, Christopher A. Lenyk, Trevor A . Gustafson, Sergey A. Basun, Larry E. Halliburton, Nancy C. Giles

Faculty Publications

Electron paramagnetic resonance (EPR) is used to experimentally determine the (0/−) level of the Mg acceptor in an Mg-doped β-Ga₂O₃ crystal. Our results place this level 0.65 eV (±0.05 eV) above the valence band, a position closer to the valence band than the predictions of several recent computational studies. The crystal used in this investigation was grown by the Czochralski method and contains large concentrations of Mg acceptors and Ir donors, as well as a small concentration of Fe ions and an even smaller concentration of Cr ions. Below room temperature, illumination with 325 nm laser light …

Sulfur Dioxide From The Atmospheric Chemistry Experiment Satellite, Doug Cameron

College of Sciences Posters

The version 4.0 dataset from the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) on SCISAT, released in March of 2019, has sulfur dioxide (SO₂) volume mixing ratio (VMR) profiles as a routine data product. From this dataset, global SO₂ distributions between the altitudes of 10.5 km and 23.5 km are analyzed. The global distribution of all SO₂ VMR data by altitude is broken down into 30° and 5° latitude zones. Seasonality of the global SO₂ distribution is explored. Volcanic SO₂ plumes are isolated in the dataset and compared with extinction data from the …

The Clas12 Software Framework And Event Reconstruction, V. Ziegler, N. A. Baltzell, F. Bossù, D. S. Carman, P. Chatanon, M. Contalbrigo, J. Newton, M. Ungaro

Physics Faculty Publications

We describe offline event reconstruction for the CEBAF Large Acceptance Spectrometer at 12 GeV (CLAS12), including an overview of the offline reconstruction framework and software tools, a description of the algorithms developed for the individual detector subsystems, and the overall approach for charged and neutral particle identification. We also present the scheme for data processing and the code management procedures.

The Breakup Of A Helium Cluster After Removing Attractive Interaction Among A Significant Number Of Atoms In The Cluster, Tao Pang

Physics & Astronomy Faculty Research

The breakup of a quantum liquid droplet is examined through a 4He cluster by removing the attractive tail in the interaction between some of the atoms in the system with the diffusion quantum Monte Carlo simulation. The ground-state energy, kinetic energy, cluster size, and density profile of the cluster are evaluated against the percentage of the atoms without the attractive tail. The condition for the cluster to lose its ability to form a quantum liquid droplet at zero temperature is found and analyzed. The cluster is no longer able to form a quantum liquid droplet when about two-thirds of pairs …

Single-Pulse, Kerr-Effect Mueller Matrix Lidar Polarimeter, Keyser, Christian K., Richard K. Martin, Helena Lopez-Aviles, Khanh Nguyen, Arielle M. Adams, Demetrios Christodoulides

Faculty Publications

We present a novel light detection and ranging (LiDAR) polarimeter that enables measurement of 12 of 16 sample Mueller matrix elements in a single, 10 ns pulse. The new polarization state generator (PSG) leverages Kerr phase modulation in a birefringent optical fiber, creating a probe pulse characterized by temporally varying polarization. Theoretical expressions for the Polarization State Generator (PSG) Stokes vector are derived for birefringent walk-off and no walk-off and incorporated into a time-dependent polarimeter signal model employing multiple polarization state analyzers (PSA). Polarimeter modeling compares the Kerr effect and electro-optic phase modulator–based PSG using a single Polarization State Analyzer …

Enhancement And Reentrance Of Spin Triplet Superconductivity In Ute₂ Under Pressure, Sheng Ran, Hyunsoo Kim, I. Lin Liu, Shanta R. Saha, Ian Hayes, Tristin Metz, Yun Suk Eo, Johnpierre Paglione, Nicholas P. Butch

Physics Faculty Research & Creative Works

Spin triplet superconductivity in the Kondo lattice UTe₂ appears to be associated with spin fluctuations originating from incipient ferromagnetic order. Here we show clear evidence of twofold enhancement of superconductivity under pressure, which discontinuously transitions to magnetic order, likely of ferromagnetic nature, at higher pressures. The application of a magnetic field tunes the system back across a first-order phase boundary. Straddling this phase boundary, we find another example of reentrant superconductivity in UTe₂. As the superconductivity and magnetism exist on two opposite sides of the first-order phase boundary, our results indicate other microscopic mechanisms may be playing …

Toros Optical Follow-Up Of The Advanced Ligo–Virgo O2 Second Observational Campaign, Rodolfo Artola, Martin Beroiz, Juan Cabral, R. Camuccio, Moises Castillo, Mario C. Diaz, Aldo Fonrouge, Alejandro F. Hinojosa, Andrea Hinojosa, Americo F. Hinojosa, Wendy Mendoza, Victor Perez, Tania Peñuela, Wahltyn Rattray, Ervin Vilchis, Adam Zadrozny

Physics and Astronomy Faculty Publications and Presentations

We present themethods and results of the optical follow-up, conducted by the Transient Optical Robotic Observatory of the South Collaboration, of gravitational wave events detected during the Advanced LIGO–Virgo second observing run (2016 November–2017 August). Given the limited field of view (∼100 arcmin) of our observational instrumentation, we targeted galaxies within the area of high localization probability that were observable from our sites. We analysed the observations using difference imaging, followed by a random forest algorithm to discriminate between real and spurious transients. Our observations were conducted using telescopes at Estacion Astrofısica de Bosque Alegre, Cerro Tololo Inter-American Observatory, the …

A 3-Year Sample Of Almost 1,600 Elves Recorded Above South America By The Pierre Auger Cosmic-Ray Observatory, A. Aab, P. Abreu, M. Aglietta, I. F.M. Albuquerque, J. M. Albury, I. Allekotte, David Nitz, Et. Al.

Michigan Tech Publications

©2020. The Authors. Elves are a class of transient luminous events, with a radial extent typically greater than 250 km, that occur in the lower ionosphere above strong electrical storms. We report the observation of 1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located in the Mendoza province of Argentina with a viewing footprint for elve observations of 3.106 km2, reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for severe convective …

Fabrication And Characterization Of Perovskite Structures For Solar Cell Applications, Asma Obaid Said Al Ghaithi

Physics Theses

Solution-processing organic–inorganic hybrid perovskites have emerged as new generation and promising light-harvesting materials for photovoltaic technology and photonic applications such as solar cells, light emitting diodes and laser. The aim of this thesis is to boost the power conversion efficiency of planer perovskite solar cell by either using perovskite structure layer, or by doping perovskite thin film with metal ion to enhance the morphological, structure and optical properties of the perovskite thin film.

The first proposed perovskite layer is based on CH₃NH₃PbBr₃ and was fabricated using one step self-assembly method. The method is appropriate to produce CH₃NH₃PbBr₃ microstructures in form …

Giving Students A Better Understanding Of The Concepts Behind The Coriolis Force, Ridge Cole

Physics Capstone Projects

The Coriolis force is a physical phenomenon that has proven difficult for students to understand for centuries. While the mathematical approach to teaching this phenomenon is well known and outlined, the concepts behind this force have proven to be very elusive to students. Through the use of modern technology and new ways of presenting these concepts, we hope to give students a clear understanding of the Coriolis force in the future.

Dynamics Of Subsiding Shells In Actively Growing Clouds With Vertical Updrafts, Vishnu Nair, Thijs Heus, Maarten Van Reeuwijk

Physics Faculty Publications

© 2020 American Meteorological Society. The dynamics of a subsiding shell at the edges of actively growing shallow cumulus clouds with updrafts is analyzed using direct numerical simulation. The actively growing clouds have a fixed in-cloud buoyancy and velocity. Turbulent mixing and evaporative cooling at the cloud edges generate a subsiding shell that grows with time. A self-similar regime is observed for first-and second-order moments when normalized with respective maximum values. Internal scales derived from integral properties of the flow problem are identified. A self-similarity analysis using these scales reveals that contrary to classical self-similar flows, the turbulent kinetic energy …

Primary Cilia Have A Length-Dependent Persistence Length, Justin Flaherty, Zhe Feng, Zhangli Peng, Y. N. Young, Andrew Resnick

Physics Faculty Publications

© 2019, The Author(s). The fluctuating position of an optically trapped cilium tip under untreated and Taxol-treated conditions was used to characterize mechanical properties of the cilium axoneme and its basal body by combining experimental, analytical,and computational tools. We provide, for the first time, evidence that the persistence length of a ciliary axoneme is length-dependent; longer cilia are stiffer than shorter cilia. We demonstrate that this apparent length dependence can be understood by a combination of modeling axonemal microtubules as anisotropic elastic shells and including actomyosin-driven stochastic basal body motion.Our results also demonstrate the possibility of using observable ciliary dynamics …

Constraining The Local Burst Rate Density Of Primordial Black Holes With Hawc, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, H. A.Ayala Solares, V. Baghmanyan, E. Belmont-Moreno, S. Y. Benzvi, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, E. De La Fuente, C. De León, B. L. Dingus, M. A. Duvernois, J. C. Díaz-Vélez, R. W. Ellsworth, K. L. Engel, C. Espinoza, H. Fleischhack, N. Fraija, A. Galván-Gámez, J. A. García-González, F. Garfias, M. M. González, J. A. Goodman, B. Hona, D. Huang, Petra Huentemeyer

Michigan Tech Publications

Primordial Black Holes (PBHs) may have been created by density fluctuations in the early Universe and could be as massive as > 109 solar masses or as small as the Planck mass. It has been postulated that a black hole has a temperature inversely-proportional to its mass and will thermally emit all species of fundamental particles via Hawking Radiation. PBHs with initial masses of ∼ 5 × 1014 g (approximately one gigaton) should be expiring today with bursts of high-energy gamma radiation in the GeV-TeV energy range. The High Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays with energies …

Many-Body Quantum Dynamics And Induced Correlations Of Bose Polarons, Simeon I. Mistakidis, G. M. Koutentakis, Garyfallia Katsimiga, Th Busch, P. Schmelcher

Physics Faculty Research & Creative Works

We Study The Ground State Properties And Non-Equilibrium Dynamics Of Two Spinor Bosonic Impurities Immersed In A One-Dimensional Bosonic Gas Upon Applying An Interspecies Interaction Quench. For The Ground State Of Two Non-Interacting Impurities We Reveal Signatures Of Attractive Induced Interactions In Both Cases Of Attractive Or Repulsive Interspecies Interactions, While A Weak Impurity-Impurity Repulsion Forces The Impurities To Stay Apart. Turning To The Quench Dynamics We Inspect The Time-Evolution Of The Contrast Unveiling The Existence, Dynamical Deformation And The Orthogonality Catastrophe Of Bose Polarons. We Find That For An Increasing Postquench Repulsion The Impurities Reside In A Superposition Of …

Heavy Quark Expansion For Heavy-Light Light-Cone Operators, Shuai Zhao

Physics Faculty Publications

We generalize the celebrated heavy quark expansion to nonlocal QCD operators. By taking nonlocal heavy-light current on the light-cone as an example, we confirm that the collinear singularities are common between QCD operator and the corresponding operator in heavy quark effective theory (HQET), at the leading power of 1/M expansion. Based on a perturbative calculation in operator form at one-loop level, a factorization formula linking QCD and HQET operators is investigated and the matching coefficient is determined. The matching between QCD and HQET light-cone distribution amplitudes (LCDAs) as well as other momentum distributions of hadron can be derived as …

Towards A Real-Time Fully-Coherent All-Sky Search For Gravitational Waves From Compact Binary Coalescences Using Particle Swarm Optimization, M. E. Normandin, Soumya Mohanty

Physics and Astronomy Faculty Publications and Presentations

While a fully-coherent all-sky search is known to be optimal for detecting gravitational wave signals from compact binary coalescences, its high computational cost has limited current searches to less sensitive coincidence-based schemes. Following up on previous work that has demonstrated the effectiveness of particle swarm optimization (PSO) in reducing the computational cost of this search, we present an implementation that achieves near real-time computational speed. This is achieved by combining the search efficiency of PSO with a significantly revised and optimized numerical implementation of the underlying mathematical formalism along with additional multithreaded parallelization layers in a distributed computing framework. For …

Quantum Interference Of K Capture In Energetic G E31+(1s)-Kr Collisions, R. Schuch, Michael Schulz, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We have measured characteristic K x rays in coincidence with the scattered particles from collisions of hydrogenlike Ge ions with Kr atoms. The ions were first accelerated to 8.6 MeV/amu, post-stripped to H-like charge state, and decelerated to around 2.5 MeV/amu. From the measurements the probabilities for K-shell to K-shell charge transfer as a function of collision impact parameters were obtained. The probabilities show an onset of oscillations which are interpreted as quantum interference between the K-shell to K-shell electron transfer amplitudes in two spatially separated coupling regions in the incoming and outgoing parts of the collision. The probabilities of …

What Can Scattered Light Tell You About Your Favorite Magnetic Material?: A Magneto Optical Investigation Of The Magnetic Properties Of Aligned Janus Fiber Agglomerates.Influence Of Dynamic Multiaxial Transverse Loading On Ultrahigh Molecular Weight Polyethylene Single Fiber Failure, Cory John Dolbashian

Theses and Dissertations

Here we seek to take a traditional Magneto Optic Kerr Effect (MOKE) experimental design, useful for local magnetization measurements, and apply it to measuring aligned multiferroic Janus nano fiber agglomerates. In order to achieve this we modify the traditional MOKE geometry by measuring our Kerr rotation from collimated scattered light, rather than the conventional specular reflection. Using various techniques to improve signal to noise ratio (SNR), we extend the application of this scattered MOKE geometry to build families of First Order Reversal Curves (FORC). Using an alternative analysis technique, FORC curves are processed and become a FORC diagram, which is …

Probing The Interstellar Medium Of Galaxies Using Gravitationally Lensed Sight Lines And The Relevant Atomic Physics, Frances Cashman

Theses and Dissertations

Absorption spectroscopy of gravitationally lensed quasars (GLQs) enables study of spatial variations in the interstellar and/or circumgalactic medium (ISM, CGM) of foreground galaxies. In this work I present observations of 4 GLQs, each with two images separated by 0.8-3.000, that show strong absorbers at redshifts 0.4 abs< 1.3 in their spectra, including some at the lens redshift. The H I Lyman lines were measured in five absorbers using HST-STIS, and metal lines with either the MagE spectrograph or the Sloan Digital Sky Survey. These data, combined with the literature, show no strong correlation between absolute values of differences in NH I, NFe II, or [Fe/H] and sight line separations at absorber redshifts. The measured abundance gradients show a tentative anti-correlation with abundances at galaxy centers.

A study of the lens galaxy foreground to the doubly lensed quasar SBS 0909+532 reveals a large difference in H I and metal column densities between sight lines. Using archival HST-STIS and Keck HIRES spectra, log N _{H I} 18.18 cm−2 and log N _{H I} = 20.38±0.02 cm⁻²were measured, resulting …