Digital Commons Network^™

Kinetic Modeling Of Ionospheric Outflows Observed By The Visions-1 Sounding Rocket, Robert M. Albarran Ii

Doctoral Dissertations and Master's Theses

Plasma escape from the high-latitude ionosphere (ion outflow) serves as a significant source of heavy plasma to magnetospheric plasma sheet and ring current regions. Outflows alter mass density and reconnection rates, hence global responses of the magnetosphere. The VISIONS-1 (VISualizing Ion Outflow via Neutral atom imaging during a Substorm) sounding rocket was launched on Feb. 7, 2013 at 8:21 UTC from Poker Flat, Alaska, into an auroral substorm with the objective of identifying the drivers and dynamics of nightside ion outflow at altitudes where it is initiated, below 1000 km. Energetic ion data from the VISIONS-1 polar cap boundary crossing …

Retrieval Of The Molecular Orientation Distribution From Atom-Pair Angular Distributions, Yanwei Xiong, Kyle J. Wilkin, S. K. Saha, Sri Bhavya Muvva, Haoran Zhao, Martin Centurion

Department of Physics and Astronomy: Faculty Publications

Imaging laser-induced rotational dynamics is an important and active field due to its applications in capturing reactions in the molecular frame and in molecular imaging. Experimental measurement of the molecular orientation distribution, as a function of the Euler angles, has been demonstrated for special cases when the detectable signal is generated along the molecular symmetry axis. Here we developed the general theory that maps the probability density distribution of the molecular orientation to the atom-pair angular distributions for nonlinear molecules. With the theory, the molecular orientation distribution can be retrieved from the measured atom-pair angular distribution, which we demonstrate experimentally …

Positronium Collisions With Polar Molecules, R. S. Wilde, M. K. Selvage, Ilya I. Fabrikant

Department of Physics and Astronomy: Faculty Publications

We calculate elastic and positronium (Ps) break-up cross sections for collisions of Ps with the polar molecules CO, HCl, and LiF in the fixed-nuclei approximation. We incorporate electron exchange and correlation for these processes by using the free-electron-gas model developed earlier for Ps scattering by rare-gas atoms, N₂, O₂, and CO₂ molecules. The present target molecules provide a range of dipole moments from the weakly polar CO to the strongly polar LiF. We find that Ps scattering is similar to electron scattering when the cross sections are plotted as a function of projectile velocity for …

Nonuniversality Of Quantum Noise In Optical Amplifiers Operating At Exceptional Points, L. Simonson, S. K. Ozdemir, A. Eisfeld, A. Metelmann, R. El-Ganainy

Michigan Tech Publications, Part 1

The concept of exceptional points-based optical amplifiers (EPOAs) has been recently proposed as a new paradigm for miniaturizing optical amplifiers while simultaneously enhancing their gain-bandwidth product. While the operation of this new family of amplifiers in the classical domain provides a clear advantage, their performance in the quantum domain has not yet been evaluated. Particularly, it is not clear how the quantum noise introduced by vacuum fluctuations will affect their operation. Here, we investigate this problem by considering three archetypal EPOA structures that rely either on unidirectional coupling, parity-time symmetry, or particle-hole symmetry for implementing the exceptional point. By using …

Dirac Dark Matter, Neutrino Masses, And Dark Baryogenesis, Diego Restrepo, Andrès Rivera, Walter Tangarife

Physics: Faculty Publications and Other Works

We present a gauged baryon number model as an example of models where all new fermions required to cancel out the anomalies help to solve phenomenological problems of the standard model (SM). Dark fermion doublets, along with the isosinglet charged fermions, in conjunction with a set of SM-singlet fermions, participate in the generation of small neutrino masses through the Dirac-dark Zee mechanism. The other SM-singlets explain the dark matter in the Universe, while their coupling to an inert singlet scalar is the source of the CP violation. In the presence of a strong first-order electroweak phase transition, this “dark” CP …

Search For Numi Mudar Electron Neutrinos In Microboone, Ohana Benevides Rodrigues

Dissertations - ALL

Muon Decay-at-Rest (μDAR) produces electron-neutrinos (νe) in the 0 to 53 MeV energy range. The given range is especially interesting for its similarity to Supernovae-produced νe. The Deep Underground Neutrino Experiment (DUNE) has as one of its main goals to measure Supernovae neutrinos on the occasion of a Galactic Supernova burst. To optimize the chances of detection, a low-energy neutrino-LAr cross-section (XS) measurement is a piece of important information to have at hand. MicroBooNE presents a good opportunity to explore the low-energy ν-LAr detection and XS using the μDAR neutrinos and therefore develop the tools necessary for DUNE to interpret …

Combining Freestanding Ferroelectric Perovskite Oxides With Two-Dimensional Semiconductors For High Performance Transistors, Sergio Puebla, Thomas Pucher, Victor Rouco, Gabriel Sanchez-Santolino, Yong Xie, Victor Zamora, Fabian A. Cuellar, Federico J. Mompean, Carlos Leon, Carlos O. Island, Mar Garcia-Hernandez, Jacobo Santamaria, Carmen Munuera, Andres Castellanos-Gomez

Physics & Astronomy Faculty Research

We demonstrate the fabrication of field-effect transistors based on single-layer MoS2 and a thin layer of BaTiO3 (BTO) dielectric, isolated from its parent epitaxial template substrate. Thin BTO provides an ultrahigh-κ gate dielectric effectively screening Coulomb scattering centers. These devices show mobilities substantially larger than those obtained with standard SiO2 dielectrics and comparable with values obtained with hexagonal boron nitride, a dielectric employed for fabrication of high-performance two-dimensional (2D) based devices. Moreover, the ferroelectric character of BTO induces a robust hysteresis of the current vs gate voltage characteristics, attributed to its polarization switching. This hysteresis is strongly suppressed when the …

On An Adaptation Of The Reynolds Number, Applicable To Body-Caudal-Fin Aquatic Locomotion, Roi Gurka, Asif Shahriar Nafi, Daniel Weihs

Physics and Engineering Science

The Reynolds number, which describes the relative importance of viscous and inertial contributions is commonly used to analyze forces on fish and other aquatic animals. However, this number is based on steady, time-independent conditions, while all swimming motions have a periodic component. Here we apply periodic flow conditions to define a new non-dimensional group, which we name the “Periodic Swimming Number, P”, which rectifies this lacuna. This new non-dimensional number embodies the periodic motion and eliminates the arbitrariness of choosing a length scale in the Reynolds number for Body –Caudal-Fin (BCF) swimming. We show that the new number has the …

Random Strain Induced Correlations In Materials With Intertwined Nematic And Magnetic Orders, W. Joe Meese, Thomas Vojta, Rafael M. Fernandes

Physics Faculty Research & Creative Works

Electronic nematicity is rarely observed as an isolated instability of a correlated electron system. Instead, in iron pnictides and in certain cuprates and heavy-fermion materials, nematicity is intertwined with an underlying spin-stripe or charge-stripe state. As a result, random strain, ubiquitous in any real crystal, creates both random-field disorder for the nematic degrees of freedom and random-bond disorder for the spin or charge ones. Here, we put forward an Ashkin-Teller model with random Baxter fields to capture the dual role of random strain in nematic systems for which nematicity is a composite order arising from a stripe state. Using Monte …

A Review On Natural Gamma Radiation Dose Levels And Its Health Effects, Shankramma K, Kamsali Nagaraja, Sathish L A, Charan Kumar K

International Journal of Health and Allied Sciences

Exposure to the natural background gamma radiations in both indoor and outdoor environments is inevitable. The long-term exposure to such radiations could result in lung cancer (sometimes leukaemia, CNS tumours); and hence it must be constantly monitored. In this paper, an attempt is made to review the background natural gamma radiation doses reported at various locations for the south Indian environment and it was found that the gamma levels in coastal regions were relatively higher than those in sub continental locations but in most of the locations the annual effective dose rate was within the permissible limits as per UNSCEAR

A Blind Benchmark Of Analysis Tools To Infer Kinetic Rate Constants From Single-Molecule Fret Trajectories, Dorothy A. Erie, Lydia Kisley, Dushani Dunukara

Faculty Scholarship

Single-molecule FRET (smFRET) is a versatile technique to study the dynamics and function of biomolecules since it makes nanoscale movements detectable as fluorescence signals. The powerful ability to infer quantitative kinetic information from smFRET data is, however, complicated by experimental limitations. Diverse analysis tools have been developed to overcome these hurdles but a systematic comparison is lacking. Here, we report the results of a blind benchmark study assessing eleven analysis tools used to infer kinetic rate constants from smFRET trajectories. We test them against simulated and experimental data containing the most prominent difficulties encountered in analyzing smFRET experiments: different noise …

Pulse-Echo Quantitative Us Biomarkers For Liver Steatosis: Toward Technical Standardization, Timothy Stiles, David T. Fetzer, Ivan M. Rosado-Mendez, Michael Wang, Michelle L. Robbin, Arinc Ozturk, Keith A. Wear, Juvenal Ormachea, J. Brian Fowlkes, Timothy J. Hall, Anthony E. Samir

Natural Sciences Publications

Excessive liver fat (steatosis) is now the most common cause of chronic liver disease worldwide and is an independent risk factor for cirrhosis and associated complications. Accurate and clinically useful diagnosis, risk stratification, prognostication, and therapy monitoring require accurate and reliable biomarker measurement at acceptable cost. This article describes a joint effort by the American Institute of Ultrasound in Medicine (AIUM) and the RSNA Quantitative Imaging Biomarkers Alliance (QIBA) to develop standards for clinical and technical validation of quantitative biomarkers for liver steatosis. The AIUM Liver Fat Quantification Task Force provides clinical guidance, while the RSNA QIBA Pulse-Echo Quantitative Ultrasound …

Search For A W' Boson Decaying To A Vector-Like Quark And A Top Or Bottom Quark In The All-Jets Final State At √S = 13 Tev, The Cms Collaboration

Department of Physics and Astronomy: Faculty Publications

A search is presented for a heavy W0 boson resonance decaying to a B or T vector-like quark and a t or a b quark, respectively. The analysis is performed using protonproton collisions collected with the CMS detector at the LHC. The data correspond to an integrated luminosity of 138 fb⁻¹ at a center-of-mass energy of 13TeV. Both decay channels result in a signature with a t quark, a Higgs or Z boson, and a b quark, each produced with a significant Lorentz boost. The all-hadronic decays of the Higgs or Z boson and of the t quark are …

Structural And Compositional Properties Of 2d Ch3nh3pbi3 Hybrid Halide Perovskite: A Dft Study, Sandip R. Kumavat, Geeta Sachdeva, Yogesh Sonvane, Sanjeev K. Gupta

Michigan Tech Publications, Part 1

Two-dimensional (2D) hybrid halide perovskites have been scrutinized as candidate materials for solar cells because of their tunable structural and compositional properties. Results based on density functional theory demonstrate its thickness-dependent stability. We have observed that the bandgap decreases from the mono- to quad-layer because of the transformation from 2D towards 3D. Due to the transformation, the carrier mobility is lowered with the corresponding smaller effective mass. On the other hand, the multilayer structures have good optical properties with an absorption coefficient of about 105 cm−1. The calculated absorption spectra lie between 248 nm and 496 nm, leading to optical …

Deep-Turbulence Phase Compensation Using Tiled Arrays, Mark F. Spencer, Terry J. Brennan

Faculty Publications

Tiled arrays use modulo-2π phase compensation and coherent beam combination to correct for the effects of deep turbulence. As such, this paper uses wave-optics simulations to compare the closed-loop performance of tiled arrays to a branch-point-tolerant phase reconstructor known as LSPV+7 [Appl. Opt. 53, 3821 (2014) [CrossRef] ]. The wave-optics simulations make use of a point-source beacon and are setup with weak-to-strong scintillation conditions. This setup enables a trade-space exploration in support of a power-in-the-bucket comparison with LSPV+7. In turn, the results show that tiled arrays outperform LSPV+7 when transitioning from weak-to-strong scintillation conditions. These results are both …

Pulse-Quality Metric For Nonstationary Partially Coherent Fields, Milo W. Hyde Iv, Olga Korotkova, Mark F. Spencer

Faculty Publications

This paper generalizes a pulse-quality metric referred to as P², i.e., the time analogue of Siegman’s beam quality factor M², to include pulsed (nonstationary) random fields of any state of coherence. The analysis begins with the derivation of a general P² relation, which we then specialize to the important cases of coherent and Schell-model pulsed beams. As examples, we derive the P² for two stochastic sources: (1) a cosine Gaussian-correlated Schell-model pulsed beam and (2) a nonuniformly correlated pulsed beam. For both of these sources, we generate (in simulation) random instances of each and …

Coupled Surface Plasmon–Phonon Polariton Nanocavity Arrays For Enhanced Mid-Infrared Absorption, Satya R. Kachiraju, Ivan Nekrashevich, Imtiaz Ahmad, Hira Farooq, Long Chang, Sangsik Kim, Myoung-Hwan Kim

Physics & Astronomy Faculty Publications

Resonant optical cavities are essential components in mid-infrared applications. However, typical film-type cavities require multilayer stacks with a micronthick spacer due to mid-infrared wavelengths, and their performance is limited by narrow frequency tunability and angular sensitivity. We propose and experimentally demonstrate the subwavelength-scale (≈��0/150) resonant nanocavity arrays that enhance the absorption spectrum of the device in the mid-infrared (10–12 microns) via excitation of coupled surface plasmon–phonon polaritons. The proposed metal–insulator–polar dielectric (gold–silicon–silicon carbide) structure supports a guided mode of the coupled surface polaritons in the lateral direction while vertically confining the mid-infrared wave

Measurements Of B → D(∗)−,0d(∗)+,0k+Π− Branching Fractions In The K∗0 Mass Window, Harris Bernstein

Dissertations - ALL

This thesis presents measurements of 11 branching fractions of the form B →D(∗)−,0D(∗)+,0K+π− within the K∗0 mass window using LHCb data taken in 2016, 2017 and 2018. All 11 branching fractions are measured simultaneously and are reported alongside the covariance and correlation matrices for the final measurement.

Resonant Plasmonic–Biomolecular Chiral Interactions In The Far-Ultraviolet: Enantiomeric Discrimination Of Sub-10 Nm Amino Acid Films, Tiago Ramos Leite, Lin Zschiedrich, Orhan Kizilkaya, Kevin M. Mcpeak

Faculty Publications

Resonant plasmonic–molecular chiral interactions are a promising route to enhanced biosensing. However, biomolecular optical activity primarily exists in the far-ultraviolet regime, posing significant challenges for spectral overlap with current nano-optical platforms. We demonstrate experimentally and computationally the enhanced chiral sensing of a resonant plasmonic–biomolecular system operating in the far-UV. We develop a full-wave model of biomolecular films on Al gammadion arrays using experimentally derived chirality parameters. Our calculations show that detectable enhancements in the chiroptical signals from small amounts of biomolecules are possible only when tight spectral overlap exists between the plasmonic and biomolecular chiral responses. We support this conclusion …

Constraints On The Very High Energy Gamma-Ray Emission From Short Grbs With Hawc, A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, H. A.Ayala Solares, R. Babu, E. Belmont-Moreno, C. Brisbois, K. S. Caballero-Mora, T. Capistrán, A. Carramiñana, S. Casanova, O. Chaparro-Amaro, U. Cotti, J. Cotzomi, S. Coutiño De León, C. De León, E. De La Fuente, R. Diaz Hernandez, S. Dichiara, B. L. Dingus, M. A. Duvernois, M. Durocher, J. C. Díaz-Vélez, K. Engel, C. Espinoza, K. L. Fan, N. Fraija, A. Galván-Gámez

Michigan Tech Publications, Part 1

Many gamma-ray bursts (GRBs) have been observed from radio wavelengths, and a few at very high energies (VHEs, >100 GeV). The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is well suited to study transient phenomena at VHEs owing to its large field of view and duty cycle. These features allow for searches of VHE emission and can probe different model assumptions of duration and spectra. In this paper, we use data collected by HAWC between 2014 December and 2020 May to search for emission in the energy range from 80 to 800 GeV coming from a sample of 47 short …

A Novel Rid Algorithm Of Muon Trajectory Reconstruction In Water Cherenkov Detectors, Neerav Kaushal

Michigan Tech Publications, Part 1

Cosmic rays that strike the top of the Earth’s atmosphere generate a shower of secondary particles that move toward the surface with relativistic speeds. Water Cherenkov detectors (WCDs) on the ground can detect charged muons, which are one of the many particles generated in the shower, with the Cherenkov imaging technique. A large number of these muons travel in WCD tanks near the speed of light in a vacuum, faster than the speed of light in water, and so trigger isotropic Cherenkov radiation, which is detected by the photomultiplier tubes (PMTs) placed inside the tanks. When the radial component of …

Leptogenesis Triggered By A First-Order Phase Transition, Peisi Huang, Ke-Pan Xie

Department of Physics and Astronomy: Faculty Publications

We propose a new scenario of leptogenesis, which is triggered by a first-order phase transition (FOPT). The right-handed neutrinos (RHNs) are massless in the old vacuum, while they acquire a mass in the new vacuum bubbles, and the mass gap is huge compared with the FOPT temperature. The ultra-relativistic bubble walls sweep the RHNs into the bubbles, where the RHNs experience fast decay and generate the lepton asymmetry, which is further converted to the baryon asymmetry of the Universe (BAU). Since the RHNs are out of equilibrium inside the bubble, the generated BAU does not suffer from the thermal bath …

Polarization Topology At The Nominally Charged Domain Walls In Uniaxial Ferroelectrics, Yurii Tikhonov, Jesi R. Maguire, Conor J. Mccluskey, James P. V. Mcconville, Amit Kumar, Haidong Lu, Dennis Meier, Anna Razumnaya, John Martin Gregg, Alexei Gruverman, Valerii M. Vinokur, Igor Luk’Yanchuk

Department of Physics and Astronomy: Faculty Publications

Ferroelectric domain walls provide a fertile environment for novel materials physics. If a polarization discontinuity arises, it can drive a redistribution of electronic carriers and changes in band structure, which often result in emergent 2D conductivity. If such a discontinuity is not tolerated, then its amelioration usually involves the formation of complex topological patterns, such as flux-closure domains, dipolar vortices, skyrmions, merons, or Hopfions. The degrees of freedom required for the development of such patterns, in which dipolar rotation is a hallmark, are readily found in multiaxial ferroelectrics. In uniaxial ferroelectrics, where only two opposite polar orientations are possible, it …

Watching The Clocks: Interpreting The Page-Wootters Formalism And The Internal Quantum Reference Frame Programme, Emily Adlam

Mathematics, Physics, and Computer Science Faculty Articles and Research

We discuss some difficulties that arise in attempting to interpret the Page–Wootters and Internal Quantum Reference Frames formalisms, then use a ‘final measurement’ approach to demonstrate that there is a workable single-world realist interpretation for these formalisms. We note that it is necessary to adopt some interpretation before we can determine if the ‘reference frames’ invoked in these approaches are operationally meaningful, and we argue that without a clear operational interpretation, such reference frames might not be suitable to define an equivalence principle. We argue that the notion of superposition should take into account the way in which an instantaneous …

Jammed Solids With Pins: Thresholds, Force Networks, And Elasticity, Andy L. Zhang , '22, S. A. Ridout, Celia Parts , '22, Aarushi Sachdeva , '24, Cacey Stevens Bester, K. Vollmayr-Lee, B. C. Utter, T. Brzinski, Amy Lisa Graves

Physics & Astronomy Faculty Works

The role of fixed degrees of freedom in soft or granular matter systems has broad applicability and theoretical interest. Here we address questions of the geometrical role that a scaffolding of fixed particles plays in tuning the threshold volume fraction and force network in the vicinity of jamming. Our two-dimensional simulated system consists of soft particles and fixed “pins,” both of which harmonically repel overlaps. On the one hand, we find that many of the critical scalings associated with jamming in the absence of pins continue to hold in the presence of even dense pin latices. On the other hand, …

Pulsed Electroacoustic Measurements Of Polymers Irradiated With Low Energy Monoenergetic Electrons, Zachary Gibson, Jr Dennison

Physics Student Research

Understanding the dynamics and accumulation of embedded charge in dielectric materials is paramount for many applications from HVDC power transmission to spacecraft charging. The pulsed electroacoustic (PEA) method allows for nondestructive measurements of embedded charge distributions in dielectrics. The spatial resolution of PEA measurements are typically ~10 μm. However, some of the most deleterious spacecraft charging events result from electron fluxes with 10 keV to 50 keV energies, resulting in electron ranges of 1's to 10's of μm. Due to the resolution of the PEA method and the superposition of the interfacial charge with the deposited charge distribution, it is …

The Physical Properties Of Low-Redshift Felobal Quasars. Iii. The Location And Geometry Of The Outflows, Hyunseop Choi, Karen M. Leighly, Collin Dabbieri, Donald M. Terndrup, Sarah C. Gallagher, Gordon T. Richards

Physics and Astronomy Publications

We present continued analysis of a sample of low-redshift iron low-ionization broad-absorption-line quasars (FeLoBALQs). Choi et al. presented SimBAL spectral analysis of broad-absorption-line (BAL) outflows in 50 objects. Leighly et al. analyzed the optical emission lines of 30 of those 50 objects and found that they are characterized by either a high accretion rate (L Bol/L Edd > 0.3) or low accretion rate (0.03 < L Bol/L Edd < 0.3). We report that the outflow velocity is inversely correlated with the BAL location among the high-accretion-rate objects, with the highest velocities observed in parsec-scale outflows. In contrast, the low-Eddington-ratio objects showed the opposite trend. We confirmed the known relationship between the outflow velocity and L Bol/L Edd and found that the scatter plausibly originates in the force multiplier (launch radius) in the low(high)-accretion-rate objects. A log volume filling factor between −6 and −4 was found in most outflows but was as high as −1 for low-velocity compact outflows. We investigated the relationship between the observed [O iii] emission and that predicted from the BAL gas. We found that these could be reconciled if the emission-line covering fraction depends on the Seyfert type and BAL location. The difference between the predicted and observed [O iii] luminosity is correlated with the outflow velocity, suggesting that [O iii] emission in high-Eddington-ratio objects may be broad and hidden under Fe ii emission. We suggest that the physical differences in the outflow properties as a function of location in the quasar and accretion rate point to different formation, acceleration, and confinement mechanisms for the two FeLoBALQ types.

Nustar Observations Of Intrinsically X-Ray Weak Quasar Candidates: An Obscuration-Only Scenario, Chaojun Wang, B. Luo, W. N. Brandt, D. M. Alexander, F. E. Bauer, Sarah C. Gallagher, Jian Huang, Hezhen Liu, D. Stern

Physics and Astronomy Publications

We utilize recent NuSTAR observations (co-added depth ≈55-120 ks) of PG 1001+054, PG 1254+047, and PHL 1811 to constrain their hard X-ray (≳5 keV) weakness and spectral shapes and thus to investigate the nature of their extreme X-ray weakness. These quasars showed very weak soft X-ray emission, and they were proposed to be intrinsically X-ray weak, with the X-ray coronae producing weak continuum emission relative to their optical/UV emission. However, the new observations suggest an alternative explanation. The NuSTAR 3-24 keV spectral shapes for PG 1001+054 and PHL 1811 are likely flat (effective power-law photon indices Γeff=1.0-0.6+0.5 and Γeff=1.4-0.7+0.8, respectively), …

Optical Selection Bias And Projection Effects In Stacked Galaxy Cluster Weak Lensing, Hao-Yi Wu

Physics Faculty Publications and Presentations

Cosmological constraints from current and upcoming galaxy cluster surveys are limited by the accuracy of cluster mass calibration. In particular, optically identified galaxy clusters are prone to selection effects that can bias the weak lensing mass calibration. We investigate the selection bias of the stacked cluster lensing signal associated with optically selected clusters, using clusters identified by the redMaPPer algorithm in the Buzzard simulations as a case study. We find that at a given cluster halo mass, the residuals of redMaPPer richness and weak lensing signal are positively correlated. As a result, for a given richness selection, the stacked lensing …

How Green Lakes State Park Got Its Name: The Optics And Appearance Of Fayetteville Green Lakes, Eric A. Schiff

Physics - All Scholarship

The extraordinary and variable appearance of the Fayetteville Green Lakes in the spring, summer, and fall has been the subject of journalistic and scientific attention for more than 150 years. This article addresses the subject in two sections for differing readerships. The first section is a description of the essential science for a general readership. The second section is an abstract of the science for technically knowledgeable readers. The layout of the article is designed for a folded paper flier suitable for distribution to visitors to the lakes.

The article describes the three key properties of the lakes’ waters that …