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2019

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Articles 181 - 210 of 1445

Full-Text Articles in Physics

Physics-Driven Dual-Defect Model Fits Of Voltage Step-Up To Breakdown Data In Spacecraft Polymers, Allen Andersen, Jr Dennison Oct 2019

Physics-Driven Dual-Defect Model Fits Of Voltage Step-Up To Breakdown Data In Spacecraft Polymers, Allen Andersen, Jr Dennison

Journal Articles

Overly conservative estimates of breakdown strength can increase the mass and cost of spacecraft electrostatic discharge (ESD) mitigation methods. Improved estimates of ESD likelihood in the space environment require better models of ESD distributions. The purpose of this work is to evaluate our previously proposed dual-defect model of voltage step-up-to-breakdown tests with a case study across four dielectric materials. We predicted that materials best fit by mixed Weibull distributions would exhibit better fits with the dual-defect model compared to a mean field single defect theory. Additional data for biaxially oriented polypropylene (BOPP), polyimide (PI or Kapton) from three sources, and …

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Impact Of Out-Of-Class Science And Engineering Activities On Physics Identity And Career Intentions, Robynne M. Lock, Zahra Hazari, Geoff Potvin Oct 2019

Impact Of Out-Of-Class Science And Engineering Activities On Physics Identity And Career Intentions, Robynne M. Lock, Zahra Hazari, Geoff Potvin

Department of Teaching and Learning

The number of physics bachelor’s degrees that are awarded in the United States annually is small compared to most other science, technology, engineering, and mathematics fields, and only about one-fifth of these degrees are awarded to women. Understanding the influence of students’ science and engineering experiences on career choices is critical in order to improve future efforts to increase the number of physics majors and the participation of women. In this work, we use a physics identity framework to examine the impact of out-of-class science and engineering activities on three identity dimensions and the relationship between these dimensions and physics …

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Effect Of Synthesized 3-Hydroxyflavone Solutions On The Performance Of Dye-Sensitized Solar Cells, Hasitha Mahabaduge Oct 2019

Effect Of Synthesized 3-Hydroxyflavone Solutions On The Performance Of Dye-Sensitized Solar Cells, Hasitha Mahabaduge

Georgia Journal of Science

We investigated the influence of synthesized dye combination 3-hydroxyflavone with potassium hydroxide and sodium hydroxide as photosynthesizers for dye-sensitized solar cells (DSSCs). DSSCs are classified as hybrid inorganic/organic photovoltaic cells that have been reported to have lower production costs and efficiency as high as 12%. Annealed titanium dioxide pastes on fluorine doped tin oxide was used as the front layer of the completed devices and the performance of 3-hydroxyflavone with potassium hydroxide and sodium hydroxide was compared with the performance of dyes extracted from berries. UV-vis spectroscopy was used to characterize the absorbance of the respective absorber dyes. 3-Hydroxyflavone in …

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Hemispherical Shifted Symmetry In Polar Cap Patch Occurrence: A Survey Of Gps Tec Maps From 2015–2018, Michael David, Jan Josef Sojka, Robert W. Schunk, Anthea J. Coster Oct 2019

Hemispherical Shifted Symmetry In Polar Cap Patch Occurrence: A Survey Of Gps Tec Maps From 2015–2018, Michael David, Jan Josef Sojka, Robert W. Schunk, Anthea J. Coster

All Physics Faculty Presentations

Much theoretical and observational work has been devoted to studying the occurrence of F region polar cap patches in the Northern Hemisphere; considerably less work has been applied to the Southern Hemisphere. In recent years, the Madrigal database of mappings of total electron content (TEC) has improved in Southern Hemisphere coverage, to the point that we can now carry out a study of patch frequency and occurrence. We find that Southern Hemisphere patch occurrence is very similar to that of the Northern Hemisphere with a half‐year offset, plus an offset in universal time of approximately 12 hr. This is further …

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Observation Of Τ−→Π−ΝΤE+E− And Search For Τ−→Π−Ντμ+Μ−, Y. Jin, H. Aihara, D. Epifanov, I. Adachi, S. Ai. Said, D. M. Asner, V. Aulchenko, T. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, S. Bahinipati, V. Bansal, P. Behera, M. Berger, V. Bhardwaj, T. Bilka, J. Biswal, Milind Purohit, Et. Al. Oct 2019

Observation Of Τ−→Π−ΝΤE+E− And Search For Τ−→Π−Ντμ+Μ−, Y. Jin, H. Aihara, D. Epifanov, I. Adachi, S. Ai. Said, D. M. Asner, V. Aulchenko, T. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, S. Bahinipati, V. Bansal, P. Behera, M. Berger, V. Bhardwaj, T. Bilka, J. Biswal, Milind Purohit, Et. Al.

Faculty Publications

We present the first measurements of branching fractions of rare tau-lepton decays, τ−→π−ντℓ+ℓ− (ℓ=e or μ), using a data sample corresponding to 562 fb−1 collected at a center-of-mass energy of 10.58 GeV with the Belle detector at the KEKB asymmetric-energy e+e−collider. The τ−→π−ντe+e− decay is observed for the first time with 7.0σ significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass region Mπee > 1.05 GeV=c2 is measured to be B(τ− → π …

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A Remark On How A Consciousness Model And Entanglement Can Lead Us To Quantum Communication, Victor Christianto, Robert N. Boyd, Florentin Smarandache Oct 2019

A Remark On How A Consciousness Model And Entanglement Can Lead Us To Quantum Communication, Victor Christianto, Robert N. Boyd, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In a recent paper, we describe how a model of quantum communication based on combining consciousness experiment and entanglement can serve as impetus to stop 5G-caused diseases. Therefore, in this paper we will discuss how entanglement can be explained in terms of quantum theory. This short review may be considered as an effort to bring QM into real problem solving, i.e. telecommunication.

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Three Terms Of E-Class Data For An Introductory E&M Lab, Ronald J. Tackett, Helen Mae Cothrel, Gregory N. Hassold Oct 2019

Three Terms Of E-Class Data For An Introductory E&M Lab, Ronald J. Tackett, Helen Mae Cothrel, Gregory N. Hassold

Natural Sciences Presentations & Conference Materials

No abstract provided.

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A Unified Description Of The Electrical Properties Of Low-Density Polyethylene Via The Dispersion Parameter, Zack Gibson, Megan Loveland, Jr Dennison Oct 2019

A Unified Description Of The Electrical Properties Of Low-Density Polyethylene Via The Dispersion Parameter, Zack Gibson, Megan Loveland, Jr Dennison

Physics Student Research

Low-density polyethylene is a prototypical highly disordered insulating material. This ubiquitous polymer has a variety of applications from spacecraft charging to high voltage DC power cable insulation. Therefore, the electrical properties are of great interest. The dispersion parameter, which originally appeared in a semi-empirical model to describe anomalies in permittivity data, is central to an understanding of these electrical properties. This parameter depends linearly on either temperature (low field regime) or on electric field (high field regime) and is scaled by the reciprocal of a characteristic energy. When the dispersion parameter reaches one, a transition from dispersive to non-dispersive transport …

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First Measurement Of Neutrino Oscillation Parameters Using Neutrinos And Antineutrinos By Nova, M. A. Acero, P. Adamson, L. Aliaga, T. Alion, V. Allakhverdian, S. Altakarli, N. Anfimov, A. Antoshkin, A. Aurisano, A. Back, C. Backhouse, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, S. Bending, R. Bernstein, V. Bhatnagar, Roberto Petti, Et. Al. Oct 2019

First Measurement Of Neutrino Oscillation Parameters Using Neutrinos And Antineutrinos By Nova, M. A. Acero, P. Adamson, L. Aliaga, T. Alion, V. Allakhverdian, S. Altakarli, N. Anfimov, A. Antoshkin, A. Aurisano, A. Back, C. Backhouse, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, S. Bending, R. Bernstein, V. Bhatnagar, Roberto Petti, Et. Al.

Faculty Publications

The NOvA experiment has seen a 4.4σ signal of ⊽ e appearance in a 2 GeV⊽μ beam at a distance of 810 km. Using 12.33×1020 protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ⊽μ→⊽e candidates with a background of 10.3 and 102⊽μ→⊽μ candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm 2 32 | = 2.48 +0.11 -0.06 x 10 -3 eV2 / c4 and sin2 θ23 in the ranges …

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A Computational Study Of Sleep And The Hemispheres Of The Brain, Tera Ashley Glaze Oct 2019

A Computational Study Of Sleep And The Hemispheres Of The Brain, Tera Ashley Glaze

Dissertations

Sleep and sleep cycles have been studied for over a century, and scientists have worked on modeling sleep for nearly as long as computers have existed. Despite this extensive study, sleep still holds many mysteries. Larger and more extensive sleep-wake models have been developed, and the circadian drive has been depicted in numerous fashions, as well as incorporated into scores of studies. With the ever-growing knowledge of sleep comes the need to find more ways to examine, quantify, and define it in the context of the most complex part of the human anatomy – the brain. Presented here is the …

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Fluids In Music: The Mathematics Of Pan’S Flutes, Bogdan Nita, Sajan Ramanathan Oct 2019

Fluids In Music: The Mathematics Of Pan’S Flutes, Bogdan Nita, Sajan Ramanathan

Department of Mathematics Facuty Scholarship and Creative Works

We discuss the mathematics behind the Pan’s flute. We analyze how the sound is created, the relationship between the notes that the pipes produce, their frequencies and the length of the pipes. We find an equation which models the curve that appears at the bottom of any Pan’s flute due to the different pipe lengths.

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Nanoaperture Fabrication Via Colloidal Lithography For Single Molecule Fluorescence Analysis, Ryan M. Jamiolkowski, Kevin Y. Chen, Shane A. Fiorenza, Alyssa M. Tate, Shawn H. Pfeil, Yale E. Goldman Oct 2019

Nanoaperture Fabrication Via Colloidal Lithography For Single Molecule Fluorescence Analysis, Ryan M. Jamiolkowski, Kevin Y. Chen, Shane A. Fiorenza, Alyssa M. Tate, Shawn H. Pfeil, Yale E. Goldman

Physics & Engineering Faculty Publications

In single molecule fluorescence studies, background emission from labeled substrates often restricts their concentrations to non-physiological nanomolar values. One approach to address this challenge is the use of zero-mode waveguides (ZMWs), nanoscale holes in a thin metal film that physically and optically confine the observation volume allowing much higher concentrations of fluorescent substrates. Standard fabrication of ZMWs utilizes slow and costly E-beam nano-lithography. Herein, ZMWs are made using a self-assembled mask of polystyrene microspheres, enabling fabrication of thousands of ZMWs in parallel without sophisticated equipment. Polystyrene 1 mu m dia. microbeads self-assemble on a glass slide into a hexagonal array, …

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Dissipative Correlated Dynamics Of A Moving Impurity Immersed In A Bose-Einstein Condensate, Simeon I. Mistakidis, F. Grusdt, G. M. Koutentakis, P. Schmelcher Oct 2019

Dissipative Correlated Dynamics Of A Moving Impurity Immersed In A Bose-Einstein Condensate, Simeon I. Mistakidis, F. Grusdt, G. M. Koutentakis, P. Schmelcher

Physics Faculty Research & Creative Works

We Unravel The Nonequilibrium Correlated Quantum Quench Dynamics Of An Impurity Traveling Through A Harmonically Confined Bose-Einstein Condensate In One-Dimension. For Weak Repulsive Interspecies Interactions The Impurity Oscillates Within The Bosonic Gas. At Strong Repulsions And Depending On Its Prequench Position The Impurity Moves Towards An Edge Of The Bosonic Medium And Subsequently Equilibrates. This Equilibration Being Present Independently Of The Initial Velocity, The Position And The Mass Of The Impurity Is Inherently Related To The Generation Of Entanglement In The Many-Body System. Focusing On Attractive Interactions The Impurity Performs A Damped Oscillatory Motion Within The Bosonic Bath, A Behavior …

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Charge Transport In Disordered Materials And The Dispersion Parameter, Zachary Gibson Oct 2019

Charge Transport In Disordered Materials And The Dispersion Parameter, Zachary Gibson

Physics Student Research

Charge transport in disordered solids can be described with use of a dispersion parameter. The dispersion parameter can be defined simply as either the thermal energy (low electric field regime) or the field energy (high field regime) scaled by the reciprocal of a characteristic energy of the material. A transitionary temperature and electric field are defined when the ratio of thermal or field energy over the characteristic energy is one, respectively. This indicates a transition from dispersive transport to normal transport. Dispersive transport can be described simply by the dispersion parameter for many disordered materials. Models involving the dispersion parameter …

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In Situ Investigation Of Magnetism In Metastable Phases Of Levitated Fe83b17 During Solidification, D. G. Quirinale, D. Messina, G. E. Rustan, Andreas Kreyssig, Ruslan Prozorov, Alan I. Goldman Oct 2019

In Situ Investigation Of Magnetism In Metastable Phases Of Levitated Fe83b17 During Solidification, D. G. Quirinale, D. Messina, G. E. Rustan, Andreas Kreyssig, Ruslan Prozorov, Alan I. Goldman

A. I. Goldman

In situ measurements of structure, density, and magnetization on samples of Fe83B17 using an electrostatic levitation furnace allow us to identify and correlate the magnetic and structural transitions in this system during its complex solidification process. In particular, we identify magnetic ordering in the metastable Fe23B6/ fcc Fe coherently grown structures and primitive tetragonal Fe3B metastable phase in addition to characterizing the equilibrium Fe2B phase. Our measurements demonstrate that the incorporation of a tunnel-diode oscillator circuit within an electrostatic levitation furnace enables investigations of the physical properties of high-temperature metastable structures.

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Distinct Pressure Evolution Of Coupled Nematic And Magnetic Orders In Fese, Anna E. Böhmer, Karunakar Kothapalli, Wageesha T. Jayasekara, John M. Wilde, Bing Li, Aashish Sapkota, Benjamin G. Ueland, Pinaki Das, Yumin Xiao, Wenli Bi, Jiyong Zhao, E. Ercan Alp, Sergey L. Bud’Ko, Paul C. Canfield, Alan I. Goldman, Andreas Kreyssig Oct 2019

Distinct Pressure Evolution Of Coupled Nematic And Magnetic Orders In Fese, Anna E. Böhmer, Karunakar Kothapalli, Wageesha T. Jayasekara, John M. Wilde, Bing Li, Aashish Sapkota, Benjamin G. Ueland, Pinaki Das, Yumin Xiao, Wenli Bi, Jiyong Zhao, E. Ercan Alp, Sergey L. Bud’Ko, Paul C. Canfield, Alan I. Goldman, Andreas Kreyssig

A. I. Goldman

We present a microscopic study of nematicity and magnetism in FeSe over a wide temperature and pressure range using high-energy x-ray diffraction and time-domain Mössbauer spectroscopy. The low-temperature magnetic hyperfine field increases monotonically up to ∼ 6 GPa. The orthorhombic distortion initially decreases under increasing pressure but is stabilized at intermediate pressures by cooperative coupling to the pressure-induced magnetic order. Close to the reported maximum of the superconducting critical temperature at p = 6.8 GPa , the orthorhombic distortion suddenly disappears and a new tetragonal magnetic phase occurs. The pressure and temperature evolution of the structural and magnetic order parameters …

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Heisenberg Model Analysis On Inelastic Powder Neutron Scattering Data Using Parent And K Doped Bamn2as2 Samples, Mehmet Ramazanoglu, Aashish Sapkota, Abhishek Pandey, Jagat Lamsal, Douglas L. Abernathy, Jennifer L. Niedziela, Matthew B. Stone, R. Salci, D. A. Acar, F. O. Oztirpan, Şener Ozonder, Andreas Kreyssig, Alan I. Goldman, David C. Johnston, Robert J. Mcqueeney Oct 2019

Heisenberg Model Analysis On Inelastic Powder Neutron Scattering Data Using Parent And K Doped Bamn2as2 Samples, Mehmet Ramazanoglu, Aashish Sapkota, Abhishek Pandey, Jagat Lamsal, Douglas L. Abernathy, Jennifer L. Niedziela, Matthew B. Stone, R. Salci, D. A. Acar, F. O. Oztirpan, Şener Ozonder, Andreas Kreyssig, Alan I. Goldman, David C. Johnston, Robert J. Mcqueeney

A. I. Goldman

Low temperature powder inelastic neutron scattering measurements were performed on three different powder samples; parent BaMn2As2,12.5% K-doped Ba0.875K0.125Mn2As2 and 25% K-doped Ba(0.75)K0.25Mn2As2. The Heisenberg Model involving J1‐J2‐Jz coupling constants were compared to the data by a powder integration routine using Monte Carlo integration methods. The best magnetic parameters were selected using a chi-square test where model intensities were compared to the full (q,E) dependence of magnetic scattering. A key step to this analysis is the characterization of the background which is formed mostly by phonon scattering intensities along with other sources including the magnetic impurity scattering events. The calculated powder …

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Antiferromagnetic Stacking Of Ferromagnetic Layers And Doping-Controlled Phase Competition In Ca1−X Srx Co2−Y As2, Bing Li, Yuriy Sizyuk, Nediadath S. Sangeetha, John M. Wilde, Pinaki Das, W. Tian, David C. Johnston, Alan I. Goldman, Andreas Kreyssig, Peter P. Orth, Robert J. Mcqueeney, Benjamin G. Ueland Oct 2019

Antiferromagnetic Stacking Of Ferromagnetic Layers And Doping-Controlled Phase Competition In Ca1−X Srx Co2−Y As2, Bing Li, Yuriy Sizyuk, Nediadath S. Sangeetha, John M. Wilde, Pinaki Das, W. Tian, David C. Johnston, Alan I. Goldman, Andreas Kreyssig, Peter P. Orth, Robert J. Mcqueeney, Benjamin G. Ueland

A. I. Goldman

In search of a quantum phase transition between the two-dimensional (2D) ferromagnetism of CaCo2−yAs2 and stripe-type antiferromagnetism in SrCo2 As2, we instead find evidence for 1D magnetic frustration between magnetic square Co layers. We present neutron-diffraction data for Ca1−x Srx Co2−y As2 that reveal a sequence of x -dependent magnetic transitions which involve different stacking of 2 D ferromagnetically aligned layers with different magnetic anisotropy. We explain the x-dependent changes to the magnetic order by utilizing classical analytical calculations of a 1D Heisenberg model where single-ion magnetic anisotropy and frustration of antiferromagnetic nearest- and next-nearest-layer exchange interactions are all composition …

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Crystal Growth, Microstructure, And Physical Properties Of Srmnsb2, Yong Liu, Tao Ma, Warren E. Straszheim, Farhan Islam, Brandt A. Jensen, Wei Tian, Thomas Heitmann, R. A. Rosenberg, John M. Wilde, Bing Li, Andreas Kreyssig, Alan I. Goldman, Benjamin G. Ueland, Robert J. Mcqueeney, David Vaknin Oct 2019

Crystal Growth, Microstructure, And Physical Properties Of Srmnsb2, Yong Liu, Tao Ma, Warren E. Straszheim, Farhan Islam, Brandt A. Jensen, Wei Tian, Thomas Heitmann, R. A. Rosenberg, John M. Wilde, Bing Li, Andreas Kreyssig, Alan I. Goldman, Benjamin G. Ueland, Robert J. Mcqueeney, David Vaknin

A. I. Goldman

We report on the crystal and magnetic structures and magnetic and transport properties of SrMnSb2 single crystals grown by the self-flux method. Magnetic susceptibility measurements reveal an antiferromagnetic (AFM) transition at TN=295(3) K. Above TN, the susceptibility slightly increases and forms a broad peak at T∼420 K, which is a typical feature of two-dimensional magnetic systems. Neutron diffraction measurements on single crystals confirm the previously reported C-type AFM structure below TN. Both de Haas-van Alphen (dHvA) and Shubnikov-de Haas (SdH) effects are observed in SrMnSb2 single crystals. Analysis of the oscillatory component by a Fourier transform shows that the prominent …

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Competing Magnetic Phases And Itinerant Magnetic Frustration In Srco2 As2, Bing Li, Benjamin G. Ueland, W. T. Jayasekara, D. L. Abernathy, N. S. Sangeetha, David C. Johnston, Qing-Ping Ding, Yuji Furukawa, Peter P. Orth, Andreas Kreyssig, Alan I. Goldman, Robert J. Mcqueeney Oct 2019

Competing Magnetic Phases And Itinerant Magnetic Frustration In Srco2 As2, Bing Li, Benjamin G. Ueland, W. T. Jayasekara, D. L. Abernathy, N. S. Sangeetha, David C. Johnston, Qing-Ping Ding, Yuji Furukawa, Peter P. Orth, Andreas Kreyssig, Alan I. Goldman, Robert J. Mcqueeney

A. I. Goldman

Whereas magnetic frustration is typically associated with local-moment magnets in special geometric arrangements, here we show that SrCo2As2 is a candidate for frustrated itinerant magnetism. Using inelastic neutron scattering (INS), we find that antiferromagnetic (AF) spin fluctuations develop in the square Co layers of SrCo2As2 below T approximate to 100 K centered at the stripe-type AF propagation vector of (1/2, 1/2), and that their development is concomitant with a suppression of the uniform magnetic susceptibility determined via magnetization measurements. We interpret this switch in spectral weight as signaling a temperature-induced crossover from an instability toward ferromagnetism ordering to an instability …

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Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa Oct 2019

Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

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Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft Oct 2019

Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

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Aerosol Particle And Black Carbon Emission Factors Of Vehicular Fleet In Manila, Philippines, Leizel Madueño, Simonas Kecorius, Wolfram Birmili, Thomas Müller, James Bernard Simpas, Edgar Vallar, Maria Cecilia Galvez, Mylene Cayetano, Alfred Wiedensohler Oct 2019

Aerosol Particle And Black Carbon Emission Factors Of Vehicular Fleet In Manila, Philippines, Leizel Madueño, Simonas Kecorius, Wolfram Birmili, Thomas Müller, James Bernard Simpas, Edgar Vallar, Maria Cecilia Galvez, Mylene Cayetano, Alfred Wiedensohler

Physics Faculty Publications

Poor air quality has been identified as one of the main risks to human health, especially in developing regions, where the information on physical chemical properties of air pollutants is lacking. To bridge this gap, we conducted an intensive measurement campaign in Manila, Philippines to determine the emission factors (EFs) of particle number (PN) and equivalent black carbon (BC). The focus was on public utility jeepneys (PUJ), equipped with old technology diesel engines, widely used for public transportation. The EFs were determined by aerosol physical measurements, fleet information, and modeled dilution using the Operational Street Pollution Model (OSPM). The results …

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Setup And Characterization Of A Magneto-Optical Trap Of 87rb, Christian Mulmat Oct 2019

Setup And Characterization Of A Magneto-Optical Trap Of 87rb, Christian Mulmat

Annual Student Research Poster Session

No abstract provided.

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Methodologies For Metal Functionalization Of Phosphorus Based Photopolymer Networks, Vanessa Béland Oct 2019

Methodologies For Metal Functionalization Of Phosphorus Based Photopolymer Networks, Vanessa Béland

Electronic Thesis and Dissertation Repository

Photopolymer networks with phosphonium cation, alkyl phosphine and olefin functionality were designed, synthesized and functionalized with metals by metathesis, coordination and hydrometallation reactions, respectively. The materials were strategically designed so that the metal functionalization step could be monitored and quantified. In some cases, this involved characterization by IR, NMR, or X-ray spectroscopic techniques, or by comparison to molecular analogues. It was found that by using a bi-functional photopolymer network, the material could be bi-metallized by orthogonal mechanisms. All metallized polymer networks were tested for their suitability as precursors to metal-containing ceramics. The polymers were pyrolyzed, and on analysis it was …

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How To Reconcile Randomness With Physicists' Belief That Every Theory Is Approximate: Informal Knowledge Is Needed, Ricardo Alvarez, Nick Sims, Christian Servin, Martine Ceberio, Vladik Kreinovich Oct 2019

How To Reconcile Randomness With Physicists' Belief That Every Theory Is Approximate: Informal Knowledge Is Needed, Ricardo Alvarez, Nick Sims, Christian Servin, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

In this paper, we show that physicists' intuition about randomness is not fully consistent with their belief that every theory is only approximate. We also prove that there is no formal way to reconcile these two intuitions, this reconciliation has to be informal. Thus, there are fundamental reasons why informal knowledge is needed for describing the real world.

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Complete Matching For Quasidistribution Functions In Large Momentum Effective Theory, Wei Wang, Jian-Hui Zhang, Shuai Zhao, Ruilin Zhu Oct 2019

Complete Matching For Quasidistribution Functions In Large Momentum Effective Theory, Wei Wang, Jian-Hui Zhang, Shuai Zhao, Ruilin Zhu

Physics Faculty Publications

We complete the procedure of extracting parton distribution functions (PDFs) using large momentum effective theory at leading power accuracy in the hadron momentum. We derive a general factorization formula for the quasi-PDFs in the presence of mixing and give the corresponding hard matching kernel at O(αs), both for the unpolarized and for the polarized quark and gluon quasi-PDFs. Our calculation is performed in a regularization-independent momentum subtraction scheme. The results allow us to match the nonperturbatively renormalized quasi-PDFs to normal PDFs in the presence of mixing and therefore can be used to extract flavor-singlet quark PDFs as well …

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Comparing Proton Momentum Distributions In A = 2 And 3 Nuclei Via 2H 3H And 3He (E,E′P) Measurements, R. Cruz-Torres, F. Hauenstein, A. Schmidt, D. Nguyen, D. Abrams, H. Albataineh, S. Alsalmi, D. Androic, K. Aniol, W. Armstrong, J. Arrington, H. Atac, D. Bulumulla, C. E. Hyde, V. Khachatryan, M. N.H. Rashad, L. B. Weinstein, Z. Y. Ye, J. Zhang, Jefferson Lab Hall A Tritium Collaboration Oct 2019

Comparing Proton Momentum Distributions In A = 2 And 3 Nuclei Via 2H 3H And 3He (E,E′P) Measurements, R. Cruz-Torres, F. Hauenstein, A. Schmidt, D. Nguyen, D. Abrams, H. Albataineh, S. Alsalmi, D. Androic, K. Aniol, W. Armstrong, J. Arrington, H. Atac, D. Bulumulla, C. E. Hyde, V. Khachatryan, M. N.H. Rashad, L. B. Weinstein, Z. Y. Ye, J. Zhang, Jefferson Lab Hall A Tritium Collaboration

Physics Faculty Publications

We report the first measurement of the (e, e' p) reaction cross-section ratios for Helium-3 (3He), Tritium (3H), and Deuterium (d). The measurement covered a missing momentum range of 40 ≤ pmiss ≤ 550 MeV/c, at large momentum transfer ({Q2} ≈ 1.9 (GeV/c)2) and xB > 1, which minimized contributions from non quasi-elastic (QE) reaction mechanisms. The data is compared with planewave impulse approximation (PWIA) calculations using realistic spectral functions and momentum distributions. The measured and PWIA-calculated cross-section ratios for 3He/d and 3H/d extend to just above the typical …

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Nuclear Theory And Event Generators For Charge-Changing Neutrino Reactions, J. W. Van Orden, T. W. Donnelly Oct 2019

Nuclear Theory And Event Generators For Charge-Changing Neutrino Reactions, J. W. Van Orden, T. W. Donnelly

Physics Faculty Publications

Semi-inclusive CCν cross sections based on factorized cross sections are studied for a selection of spectral function models with the objective of facilitating the choice of models for use as input into event generators. The basic formalism for such cross sections is presented along with an introduction to constructing spectral functions for simple models based on the independent-particle shell model, the relativistic Fermi gas model (RFG), and a local density approximation (LDA) based on the RFG. Spectral functions for these models are shown for 16O along with a more sophisticated model which includes nucleon-nucleon interactions [AlvarezRuso et al., Prog. …

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Lorentz And Cpt Tests Using Penning Traps, Yunhua Ding Oct 2019

Lorentz And Cpt Tests Using Penning Traps, Yunhua Ding

Physics and Astronomy Faculty Publications

The theoretical prospects for quantum electrodynamics with Lorentz-violating operators of mass dimensions up to six are revisited in this work. The dominant effects due to Lorentz and CPT violation are studied in measurements of magnetic moments of particles confined in Penning traps. Using recently reported experimental results, new coefficients for Lorentz violation are constrained and existing bounds of various coefficients are improved.

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