Physical Sciences and Mathematics Commons^™

Measurement Of Compton Scattering From The Deuteron And An Improved Extraction Of The Neutron Electromagnetic Polarizabilities, L. S. Myers, J. R. M. Annand, J. Brudvik, G. Feldman, H. W. Grießhammer, K. Hansen, S. S. Henshaw, L. Isaksson, R. Jebali, Michael A. Kovash, M. Lundin, J. A. Mcgovern, D. G. Middleton, A. M. Nathan, D. R. Phillips, B. Schröder, S. C. Stave

Physics and Astronomy Faculty Publications

The electromagnetic polarizabilities of the nucleon are fundamental properties that describe its response to external electric and magnetic fields. They can be extracted from Compton-scattering data—and have been, with good accuracy, in the case of the proton. In contradistinction, information for the neutron requires the use of Compton scattering from nuclear targets. Here, we report a new measurement of elastic photon scattering from deuterium using quasimonoenergetic tagged photons at the MAX IV Laboratory in Lund, Sweden. These first new data in more than a decade effectively double the world data set. Their energy range overlaps with previous experiments and extends …

Gauge Transformations Of The Biconformal Connection, James Thomas Wheeler

All Physics Faculty Publications

We study the changes of the biconformal gauge fields under the local rotational and dilatational gauge transformations.

Inductive Measurement Of Optically Hyperpolarized Phosphorous Donor Nuclei In An Isotopically Enriched Silicon-28 Crystal, P. Gumann, O. Patange, C. Ramanathan, H. Haas

Dartmouth Scholarship

We experimentally demonstrate the first inductive readout of optically hyperpolarized phosphorus-31 donor nuclear spins in an isotopically enriched silicon-28 crystal. The concentration of phosphorus donors in the crystal was 1.5×1015  cm−3, 3 orders of magnitude lower than has previously been detected via direct inductive detection. The signal-to-noise ratio measured in a single free induction decay from a 1  cm3 sample (≈1015 spins) was 113. By transferring the sample to an X-band ESR spectrometer, we were able to obtain a lower bound for the nuclear spin polarization at 1.7 K of ∼64%. The 31P-T2 measured with a Hahn echo sequence was …

Momentum Distributions For 2H (E, E' P), William P. Ford, Sabine Jeschonnek, J. W. Van Orden

Faculty Publications

Background: A primary goal of deuteron electrodisintegration is the possibility of extracting the deuteron momentum distribution. This extraction is inherently fraught with difficulty, as the momentum distribution is not an observable and the extraction relies on theoretical models dependent on other models as input.

Purpose: We present a new method for extracting the momentum distribution which takes into account a wide variety of model inputs thus providing a theoretical uncertainty due to the various model constituents. To test the extraction, pseudodata were generated, and the extracted “experimental” distribution, which has theoretical uncertainty accounted by this extraction method, can be compared …

Sulfur Vacancies In Photorefractive Sn2P2S6 Crystals, Eric M. Golden, Sergey A. Basun, A. A. Grabar, I. M. Stoika, Nancy C. Giles, D. R. Evans, Larry E. Halliburton

Faculty Publications

A photoinduced electron paramagnetic resonance (EPR) spectrum in single crystals of Sn2P2S6 (SPS) is assigned to an electron trapped at a sulfur vacancy. These vacancies are unintentionally present in undoped SPS crystals and are expected to play an important role in the photorefractive behavior of the material. Nonparamagnetic sulfur vacancies are formed during the initial growth of the crystal. Subsequent illumination below 100 K with 442 nm laser light easily converts these vacancies to EPR-active defects. The resulting S = 1/2 spectrum shows well-resolved and nearly isotropic hyperfine interactions with two P ions and two Sn ions. Partially resolved interactions …

Investigation Of Emic Wave Scattering As The Cause For The Barrel 17 January 2013 Relativistic Electron Precipitation Event: A Quantitative Comparison Of Simulation With Observations, Zan Li, Robyn M. Millan, Mary K. Hudson, Leslie A. Woodger, David M. Smith, Yue Chen, R. Friedel, J. V. Rodriguez, Mark J. Engebretson, J. Goldstein, Joseph F. Fennell, Harlan E. Spence

Physics & Astronomy

Abstract

Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was observed by one of the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) balloons and was magnetically mapped close to Geostationary Operational Environmental Satellite (GOES) 13. We simulate the relativistic electron pitch angle diffusion caused by gyroresonant interactions with EMIC waves using wave and particle data measured by multiple instruments on board GOES 13 and the Van Allen Probes. We show that the count rate, the energy …

Potential Energy Curves And Associated Line Shape Of Alkali-Metal And Noble-Gas Interactions, Larry A. Blank

Theses and Dissertations

Recent interest in optically-pumped alkali laser systems has prompted this study into the binary interaction potentials between species of alkali-metal and rare-gas atoms and the effects of the collision of these species on the alkali-metal atom absorption spectrum. Special attention is placed on the relationship of the interaction potentials and the resulting line shape. The X²Σ⁺_1/2, A²π_1/2, A²π_3/2, and B²Σ⁺_1/2 potential energy curves and associated dipole matrix elements are computed for M+ Ng at the spin-orbit multi-reference configuration interaction level, where M = …

Rainich-Type Conditions For Perfect Fluid Spacetimes, Dionisios Krongos, Charles G. Torre

Research Vignettes

In this worksheet we describe and illustrate a relatively simple set of new Rainich-type conditions on an n-dimensional spacetime which are necessary and sufficient for it to define a perfect fluid solution of the Einstein field equations. Procedures are provided which implement these Rainich-type conditions and which reconstruct the perfect fluid from the metric. These results provide an example of the idea of geometrization of matter fields in general relativity, which is a purely geometrical characterization of matter fields via the Einstein field equations.

Electron Parallel Closures For Arbitrary Collisionality, Jeong-Young Ji, Eric D. Held

All Physics Faculty Publications

Electron parallel closures for heat flow, viscosity, and friction force are expressed as kernel-weighted integrals of thermodynamic drives, the temperature gradient, relative electron-ion flow velocity, and flow-velocity gradient. Simple, fitted kernel functions are obtained for arbitrary collisionality from the 6400 moment solution and the asymptotic behavior in the collisionless limit. The fitted kernels circumvent having to solve higher order moment equations in order to close the electron fluid equations. For this reason, the electron parallel closures provide a useful and general tool for theoretical and computational models of astrophysical and laboratory plasmas.

Strain-Driven Growth Of Gaas(111) Quantum Dots With Low Fine Structure Splitting, Paul J. Simmonds

Physics Faculty Publications and Presentations

Symmetric quantum dots (QDs) on (111)-oriented surfaces are promising candidates for generating polarization-entangled photons due to their low excitonic fine structure splitting(FSS). However, (111) QDs are difficult to grow. The conventional use of compressive strain to drive QD self-assembly fails to form 3D nanostructures on (111) surfaces. Instead, we demonstrate that (111) QDs self-assemble under tensile strain by growing GaAs QDs on an InP(111)A substrate. Tensile GaAs self-assembly produces a low density of QDs with a symmetric triangular morphology. Coherent, tensile QDs are observed without dislocations, and the QDs luminescence at room temperature. Single QD measurements reveal low FSS with …

Nuclear Structure Aspects Of Neutrinoless Double Beta Decay, B. Alex Brown, Mihai Horoi, Roman A. Sen′Kov

Publications and Research

We decompose the neutrinoless double-beta decay matrix elements into sums of products over the intermediate nucleus with two less nucleons. We find that the sum is dominated by the J^pi=0^+ ground state of this intermediate nucleus for both the light and heavy neutrino decay processes. This provides a new theoretical tool for comparing and improving nuclear structure models. It also provides the connection to two-nucleon transfer experiments.

Identification Of Hyperhalogens In Agn(Bo2)M (N = 1–3, M = 1–2) Clusters: Anion Photoelectron Spectroscopy And Density Functional Calculations, Xiang-Yu Kong, Hong-Guang Xu, Pratik Koirala, Wei-Jun Zheng, Anil K. Kandalam, Puru Jena

Anil K. Kandalam

No abstract provided.

Galaxy Zoo: Candels Barred Discs And Bar Fractions, B. D. Simmons, Thomas Melvin, Chris Lintott, Karen L. Masters, Kyle W. Willett, William C. Keel, R. J. Smethurst, Edmond Cheung, Robert C. Nichol, Kevin Schawinski, Michael Rutkowski, Jeyhan S. Kartaltepe, Eric F. Bell, Kevin R. V. Casteels, Christopher J. Conselice, Omar Almaini, Henry C. Ferguson, Lucy Fortson, William Hartley, Dale D. Kocevski, Anton M. Koekemoer, Daniel H. Mcintosh, Alice Mortlock, Jeffrey A. Newman, Jamie Owensworth, Steven Bamford, Tomas Dahlen, Sandra M. Faber, Steven L. Finkelstein, Adriano Fontana, Audrey Galametz, N. A. Grogin, Ruth Grützbauch, Yicheng Guo, Boris Häußler, Kian J. Jek, Sugata Kaviraj, Ray A. Lucas, Michael Peth, Mara Salvato, Tommy Wiklind, Stijn Wuyts

Physics and Astronomy Faculty Publications

The formation of bars in disc galaxies is a tracer of the dynamical maturity of the population.

The remainder of the abstract is available at:

http://dx.doi.org/10.1093/mnras/stu1817

Hiv-1 Tat Membrane Interactions Probed Using X-Ray And Neutron Scattering, Cd Spectroscopy And Md Simulations., Kiyotaka Akabori, Kun Huang, Bradley Treece, Michael Jablin, Brian Maranville, Arthur Woll, John Nagle, Angel Garcia, Stephanie Tristram-Nagle

Prof. Stephanie Tristram-Nagle Ph.D.

We report the effect on lipid bilayers of the Tat peptide Y47GRKKRRQRRR57 from the HIV-1 virus transactivator of translation (Tat) protein. Synergistic use of low-angle X-ray scattering (LAXS) and atomistic molecular dynamic simulations (MD) indicate Tat peptide binding to neutral dioleoylphosphocholine (DOPC) lipid headgroups. This binding induced the local lipid phosphate groups to move 3Å closer to the center of the bilayer. Many of the positively charged guanidinium components of the arginines were as close to the center of the bilayer as the locally thinned lipid phosphate groups. LAXS data for DOPC, DOPC/dioleoylphosphoethanolamine (DOPE), DOPC/dioleoylphosphoserine (DOPS), and a mimic of …

What Are The True Values Of The Bending Modulus Of Simple Lipid Bilayers?, John Nagle, Michael Jablin, Stephanie Tristram-Nagle, Kiyotaka Akabori

Prof. Stephanie Tristram-Nagle Ph.D.

Values of the bending modulus KC are reviewed, and possible causes for the considerable differences are discussed. One possible cause is the use of glucose and sucrose in the classical micromechanical manipulation and shape analysis methods. New data, using the more recent low angle X-ray method, are presented that do not support an effect of glucose or sucrose on KC. Another possible cause is using an incomplete theory to interpret the data. Adding a tilt term to the theory clearly does not affect the value obtained from the shape analysis method. It is shown that a tilt term, using a …

Stratified Turbulence In The Nearshore Coastal Ocean: Dynamics And Evolution In The Presence Of Internal Bores, Ryan K. Walter, Michael E. Squibb, C. Brock Woodson, Jeffrey R. Koseff, Stephen G. Monismith

Physics

High-frequency measurements of stratified turbulence throughout the water column were collected over a 2 week period in the nearshore environment of southern Monterey Bay, CA, using a cabled observatory system and an underwater turbulence flux tower. The tower contained a vertical array of acoustic Doppler velocimeters and fast-response conductivity-temperature sensors, providing a nearly continuous data set of turbulent velocity and density fluctuations and a unique look into the stratified turbulence field. The evolution of various turbulence quantities and direct measurements of the vertical turbulent diffusivity is examined in the presence of nearshore internal bores, both in the near-bed region and …

Gas Detection Applications Of Vertically Aligned Metal Oxide Nanowire Arrays, Haiqiao Su

University of New Orleans Theses and Dissertations

To build novel electronic noses for mimicking biological olfactory systems that consist of olfactory receptor arrays with large surface area and massively-diversified chemical reactivity, three dimensional (3D) vertical aligned ZnO nanowire arrays were employed as active materials for gas detection. ZnO nanowire arrays share 3D structures similar to mammalian olfactory receptor arrays, with thousands of vertical nanowires providing a high reception area which can significantly enhance the sensors’ sensitivity. Meanwhile, with different material decorations (such as SnO₂, In₂O₃, WO₃ and polymers), each array of nanowires can produce a distinguishable response for each separate …

Electrostatic Force Microscopy And Electrical Isolation Of Etched Few-Layer Graphene Nano-Domains, D. Patrick Hunley, Abhishek Sundararajan, Mathias J. Boland, Douglas R. Strachan

Physics and Astronomy Faculty Publications

Nanostructured bi-layer graphene samples formed through catalytic etching are investigated with electrostatic force microscopy. The measurements and supporting computations show a variation in the microscopy signal for different nano-domains that are indicative of changes in capacitive coupling related to their small sizes. Abrupt capacitance variations detected across etch tracks indicates that the nano-domains have strong electrical isolation between them. Comparison of the measurements to a resistor-capacitor model indicates that the resistance between two bi-layer graphene regions separated by an approximately 10 nm wide etch track is greater than about 1×10¹² Ω with a corresponding gap resistivity greater than about …

Deriving The Dyer-Roeder Equation From The Geodesic Deviation Equation Via The Newman Penrose Null Tetrad, Aly Aly

Honors Program Theses and Projects

In this paper we examine the geodesic deviation equation using the Newman-Penrose (N-P) formalism for a flat Friedmann-Lemaitre-Robertson-Walker (FLRW) metric (Carroll, S. (2004); Ryden, B. (2003); Newman & Penrose (1962)). We solved the geodesic deviation equation for angular diameter distance, using the relevant N-P components, and the resulting expression was the Dyer-Roeder equation of cosmology (Ryden, B. (2003)) (Schneider et al. (1992)). This leads us to believe that we can apply the N-P formalism to a perturbed FLRW metric and find a solvable equation for angular diameter distance (Kling & Campbell (2008)). The perturbed FLRW metric incorporates clumps of matter …

Suncircles: A Prose/Poem 12/18/2014, Charles Kay Smith

Charles Kay Smith

A current project is writing a book of poetry. The different kind of poetry I’m trying to write melds science, humanities, and aesthetic aims of clarity and a polished plain style with social consciousness. I’m uploading one of the poems in the collection as an example of the kind of poetry I’m trying to compose.

Evidence For (And Against) Progenitor Bias In The Size Growth Of Compact Red Galaxies, Stephanie K. Keating, Roberto G. Abraham, Ricardo Schiavon, Genevieve Graves, Ivana Damjanov, Renbin Yan, Jeffrey Newman, Luc Simard

Physics and Astronomy Faculty Publications

Most massive, passive galaxies are compact at high redshifts, but similarly compact massive galaxies are rare in the local universe. The most common interpretation of this phenomenon is that massive galaxies have grown in size by a factor of about five since redshift z = 2. An alternative explanation is that recently quenched massive galaxies are larger (a "progenitor bias"). In this paper, we explore the importance of progenitor bias by looking for systematic differences in the stellar populations of compact early-type galaxies in the DEEP2 survey as a function of size. Our analysis is based on applying the statistical …

Neutral Density Behavior From 45-90 Km Based On Rayleigh Lidar Observations Above Usu, David Barton

Physics Capstone Projects

There are over 900 nights of observations taken by the Rayleigh lidar above Utah State University from 1993 to 2004. The data have been reduced to give absolute temperatures and relative densities in the mesosphere, from 45-90 km (Herron, 2004, 2007). From the 11 years of relative density data an 11-year climatology of mesospheric densities above Logan, Utah has been created. From this climatology I have been able to normalize the 11 years of density data to the following models: the MSISe00 empirical model, the CPC (Climate Prediction Center) reanalysis model, the ERA Interim reanalysis model, and the NASA MERRA …

Comparison Of Conventional And Bayesian Analysis For The Ultrasonic Characterization Of Cancellous Bone, Amber Groopman

Arts & Sciences Electronic Theses and Dissertations

This dissertation investigates the physics underlying the propagation of ultrasonic waves in cancellous bone. Although quantitative ultrasound has the potential to evaluate bone quality even better than the current gold standard X-ray based modality, its clinical utility has been hampered by the incomplete understanding of the mechanisms governing the interaction between ultrasound and bone. Therefore, studies that extend the understanding of the fundamental physics of the relationship between ultrasound and trabecular bone tissue may result in improved clinical capabilities.

Ultrasonic measurements were carried out on excised human calcaneal specimens in order to study the effects of overlapping fast and slow …

X-Ray Polarimetry With X-Calibur, Qingzhen Guo

Arts & Sciences Electronic Theses and Dissertations

ABSTRACT

X-Ray Polarimetry with X-Calibur

by

Qingzhen Guo

Doctor of Philosophy in Physics, Washington University in St. Louis,

September, 2014. Professor Henric Krawczynski, Chair

X-ray polarimetry is a prime tool to investigate the unexplored compact sources and to provide crucial information that other techniques can not produce. By measuring the degree and orientation of the polarization of radiation from a cosmic source, unique inferences about the morphology and the magnetic field structure can be made.

Krawczysnki's group at Washington University is working on a uniquely sensitive scattering polarimeter, X-Calibur, to be used in the focal plane of a focusing X-ray …

Tuning Electronic Correlation With Pressure, Gilberto Fernandes Lopes Fabbris

Arts & Sciences Electronic Theses and Dissertations

Strongly correlated electron systems display some of the most exotic ground states in condensed matter. In this thesis high pressure is used to tune the degree of electron correlations in systems of current interest. Their electronic and structural properties were investigated at high pressure using x-ray spectroscopy and scattering as well as transport techniques in a diamond anvil cell. The interplay between short- and long-range structural order, one-dimensional charge ordering, and superconductivity was studied in La_1.875Ba_0.125CuO₄. At ambient pressure, this material displays charge ordering at the onset of a low temperature structural phase transition, …

Uncertainty Relation For Mutual Information, James Schneeloch, Curtis J. Broadbent, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We postulate the existence of a universal uncertainty relation between the quantum and classical mutual informations between pairs of quantum systems. Specifically, we propose that the sum of the classical mutual information, determined by two mutually unbiased pairs of observables, never exceeds the quantum mutual information. We call this the complementary-quantum correlation (CQC) relation and prove its validity for pure states, for states with one maximally mixed subsystem, and for all states when one measurement is minimally disturbing. We provide results of a Monte Carlo simulation suggesting that the CQC relation is generally valid. Importantly, we also show that the …

Measurement Of Polarization Observables PZ, PSZ, And PCZ In Double-Pion Photoproduction Off The Proton, Yuqing Mao

Theses and Dissertations

Meson production from excited nucleons is important in the study of baryon resonances and pion photoproduction is attracting much attention. To date a rather large amount of unpolarized cross-section measurements have been reported for both single- and double-pion photoproduction. However, polarization observables provide complementary information as they probe different combinations of transition amplitudes. The database for polarization observables remains quite sparse. Double-pion photoproduction have been studied in Hall B at Jefferson Lab with linearly polarized tagged photon beams incident on longitudinally polarized protons. The experiment covered center-of-mass energies between 1.4 GeV and 2.3 GeV. The target was a FROzen Spin …

J/Ψ Polarization In P + P Collisions At √S=200 Gev In Star, James K. Adkins, Renee H. Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer

Physics and Astronomy Faculty Publications

We report on a polarization measurement of inclusive J/ψ mesons in the di-electron decay channel at mid-rapidity at 2T/c in p+p collisions at √s=200 GeV. Data were taken with the STAR detector at RHIC. The J/ψ polarization measurement should help to distinguish between different models of the J/ψ production mechanism since they predict different p_T dependences of the J/ψ polarization. In this analysis, J/ψ polarization is studied in the helicity frame. The polarization parameter λ_θ measured at RHIC becomes smaller towards high p_T, indicating …

Ferroelectric Polarization Dependent Interface Effects, Xiaohui Liu

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Utilization of the switchable spontaneous polarization of nanometer scale ferroelectric materials offers a promising avenue for future nanoelectronic devices. In this dissertation, we use density-functional calculations and phenomenological modeling to explore the effects of interface termination on thin-film heterostructures, the effects of electron doping in bulk ferroelectric materials on ferroelectric stability, and the effects of ferroelectric polarization switching on the electronic and transport properties of interfaces.

For SrRuO₃/BaTiO₃/SrRuO₃ epitaxial heterostructures grown on SrTiO₃, we find that the built-in dipole at the BaO/RuO₂ terminated interface leads to a strong preference for one polarization. …

Diffractive Optical Elements With A Large Angle Of Operation Recorded In Acrylamide Based Photopolymer On Flexible Substrates, Hoda Akbari, Izabela Naydenova, Lina Persechini, Sean Garner, Pat Cimo, Suzanne Martin

Articles

A holographic device characterised by a large angular range of operation is under development. The aim of this study is to increase the angular working range of the diffractive lens by stacking three layers of high efficiency optical elements on top of each other so that light is collected (and focussed) from a broader range of angles. The angular range of each individual lens element is important, and work has already been done in an acrylamide-based photosensitive polymer to broaden the angular range of individual elements using holographic recording at a low spatial frequency.This paper reports new results on the …