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Full-Text Articles in Physics

Free Charge Carrier Properties In Two-Dimensional Materials And Monoclinic Oxides Studied By Optical Hall Effect, Sean Knight Aug 2020

Free Charge Carrier Properties In Two-Dimensional Materials And Monoclinic Oxides Studied By Optical Hall Effect, Sean Knight

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

In this dissertation, optical Hall effect (OHE) measurements are used to determine the free charge carrier properties of important two-dimensional materials and monoclinic oxides. Two-dimensional material systems have proven useful in high-frequency electronic devices due to their unique properties, such as high mobility, which arise from their two-dimensional nature. Monoclinic oxides exhibit many desirable characteristics, for example low-crystal symmetry which could lead to anisotropic carrier properties. Here, single-crystal monoclinic gallium oxide, an AlInN/GaN-based high-electron-mobility transistor (HEMT) structure, and epitaxial graphene are studied as examples. To characterize these material systems, the OHE measurement technique is employed. The OHE is a ...


The Effect Of Chirality On Dna Threading: Exploring Binuclear Ruthenium Lntercalators Using Optical Tweezers, Adam A. Jabak May 2020

The Effect Of Chirality On Dna Threading: Exploring Binuclear Ruthenium Lntercalators Using Optical Tweezers, Adam A. Jabak

Honors Program Theses and Projects

Using optical tweezers, we have been able to study the interactions of small molecules and prospective cancer drugs with DNA. One type of these molecules, known as threading intercalators, has a flat planar intercalating moiety in between the molecule’s bulky ancillary supporting ligands. In order to bind with DNA, they have to thread their bulky ancillary ligands in between the DNA base pairs. Due to this requirement for binding, these molecules tend to have high binding affinities and slow kinetics. In this thesis, we explore the binding properties of a ruthenium-based threading intercalator -[μ-bidppz(phen)4Ru2]4+, or -P ...


Demonstrating And Testing The Deutsch-Jozsa Quantum Algorithm Towards The Realization Of Quantum Computing At Bsu, John J. Gilmore Jr. May 2020

Demonstrating And Testing The Deutsch-Jozsa Quantum Algorithm Towards The Realization Of Quantum Computing At Bsu, John J. Gilmore Jr.

Honors Program Theses and Projects

The world is changing, and fast. Quantum computing and photonic engineering are revolutionary new technologies that could change the way humans interact with information; though the eld hasn't always been that way. As with most new elds, proof of concept is needed to show that this new technology isn't just hear to stay, but it's hear to take the lead. In this, nothing is more important the the Deutsch-Jozsa Quantum algorithm; as it did just that . The majority of this research paper revolves around understanding the very essence of quantum computing. As the eld of quantum computing ...


Examining The Effect Of El Nino Phenomena And Pacific Sea Surface Temperature On The Climate Of The Glacierized White Mountains In Peru, Emily Reardon May 2020

Examining The Effect Of El Nino Phenomena And Pacific Sea Surface Temperature On The Climate Of The Glacierized White Mountains In Peru, Emily Reardon

Honors Program Theses and Projects

The purpose of this study is to determine if there is a correlation between the El Ni~no Southern Oscillation, sea surface temperatures (SST) and the climate of the Rio Santa Basin. This study is an important step in understanding the dynamics of the glaciers as a critical control on hydrological features in alpine Andes Valleys. Temperature and precipitation measurements pulled from ground based weather stations in the Rio Santa drainage basin were aggregated, synchronized, and correlated with the changes in the Pacific ocean SST o the coast of Peru and into the central Pacific. The expectation is that we ...


Image Processing Of Narrow Band Solar Eclipse Data Using Python And Maxim Dl, Rydia Hayes-Huer May 2020

Image Processing Of Narrow Band Solar Eclipse Data Using Python And Maxim Dl, Rydia Hayes-Huer

Honors Program Theses and Projects

On July 2, 2019, a total solar eclipse (TSE) was observable from Chile and Argentina. In Chile, I worked alongside the Solar Wind Sherpas, an international group led by Dr. Shadia Habbal from the University of Hawai'i Institute for Astronomy, to make observations of the solar corona and gather information about its elemental composition. Narrow band data were collected for Fe XI, Fe XIV, and Ar X. Data collected during TSE observations can be used to help solve two puzzles in solar physics: the coronal heating problem and the mechanisms responsible for the fast and slow solar winds. Narrow ...


Building A Light Current Voltage Characterization Setup For Pulsed Laser Diodes, Alec A. Milford May 2020

Building A Light Current Voltage Characterization Setup For Pulsed Laser Diodes, Alec A. Milford

Honors Program Theses and Projects

III-V laser dies are the main integrated light sources used in photonic integrated chips (PIC). Before incorporating these lasers in PICs, it is important to measure their performance and efficiency. The efficiency of these devices can be calculated from their light-current-voltage (L-I-V) characteristics. In this thesis, I will assemble the components of the probe station for the pulsed LIV setup, which are the pulse generator to drive the laser with current, temperature controller device to vary the laser’s operating temperature, and optical spectrum analyzer in order to characterize the laser’s emission wavelength. Initially this thesis was meant to ...


Measurements Of Radio Pulse Reception With Stations Of The Ara Experiment Based On The Spicecore Pulser Data Set, Jesse Osborn, Ilya Kravchenko Dr. Apr 2020

Measurements Of Radio Pulse Reception With Stations Of The Ara Experiment Based On The Spicecore Pulser Data Set, Jesse Osborn, Ilya Kravchenko Dr.

UCARE Research Products

The Askaryan Radio Array Experiment located near the South Pole works to pinpoint specific instances of neutrinos from outside the solar system interacting with nucleons inside the Antarctic ice. Neutrinos are a subatomic particle that has nearly no mass and a net neutral charge. As they are, neutrinos tend not to interact with anything as they travel through space which means they can provide us with information about events occurring far from Earth that might not be easily attained through other methods. Neutrinos are known to be emitted from a myriad of sources, including the Sun, the interaction between cosmic ...


Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse Mar 2020

Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse

Honors Theses, University of Nebraska-Lincoln

This thesis presents a quantitative study of a trochoidal electron monochromator and attempts to observe the 2p^53p^2 resonance in neon. A detailed description of the experimental apparatus, including the electron beam system, the vacuum system, and the light analysis system, is presented first. Then, we discuss the theory of how the electron beam is monochromatized, how we measured monochomatization, and how we analyze the light being emitted from the collision cell. The light analysis system is capable of accurately measuring the relative Stokes parameters for any polarization of light, and the electron beam system is capable of producing ...


Designing Writing Intensive Upper Division Laboratories In Physics, Sara Callori Feb 2020

Designing Writing Intensive Upper Division Laboratories In Physics, Sara Callori

Q2S Enhancing Pedagogy

California State University San Bernardino is currently transitioning from quarters to semesters, starting in Fall 2020. As part of this transition, the Department of Physics has transformed its curriculum to better suit the needs of its students. One major facet of this redesign has been the creation of two writing intensive, upper division laboratory courses. From a practical standpoint, under the revamped general education program, we are able to incorporate upper division writing into the major. More importantly, there are many benefits where having a writing-intensive major course aligns with program goals and professional organization recommendations. This includes designing activities ...


Edge-Coupling Of O-Band Inp Etched-Facet Lasers To Polymer Waveguides On Soi By Micro-Transfer-Printing, Ruggero Loi, Steven Kelleher, Raja Fazan Gul, Antonio Jose Trindade, David Gomez, Liam O'Faolain, Brian Corbett, Simone Iadanza, Brendan Roycroft, James O'Callaghan, Lei Liu, Kevin Thomas, Agnieszka Gocalinska, Emanuele Pelucchi, Alexander Farrell Feb 2020

Edge-Coupling Of O-Band Inp Etched-Facet Lasers To Polymer Waveguides On Soi By Micro-Transfer-Printing, Ruggero Loi, Steven Kelleher, Raja Fazan Gul, Antonio Jose Trindade, David Gomez, Liam O'Faolain, Brian Corbett, Simone Iadanza, Brendan Roycroft, James O'Callaghan, Lei Liu, Kevin Thomas, Agnieszka Gocalinska, Emanuele Pelucchi, Alexander Farrell

Cappa Publications

O-band InP etched facets lasers were heterogeneously integrated by micro-transfer-printing into a 1.54~\mu \text{m} deep recess created in the 3~\mu \text{m} thick oxide layer of a 220 nm SOI wafer. A 7\times 1.5\,\,\mu \text{m}^{2} cross-section, 2 mm long multimode polymer waveguide was aligned to the ridge post-integration by e-beam lithography with < 0.7~\mu \text{m} lateral misalignment and incorporated a tapered silicon waveguide. A 170 nm thick metal layer positioned at the bottom of the recess adjusts the vertical alignment of the laser and serves as a thermal via to sink the heat to the Si substrate. This strategy shows a roadmap for active polymer waveguide-based photonic integrated circuits.


A Case Studies Approach To Teaching Introductory Physics, Gregory A. Dilisi, Alison Chaney*, Stella Mclean*, Richard Rarick Jan 2020

A Case Studies Approach To Teaching Introductory Physics, Gregory A. Dilisi, Alison Chaney*, Stella Mclean*, Richard Rarick

2020 Faculty Bibliography

No abstract provided.


Tools For Physicistsl Creating A Major-Based Foundational Course, Carol Hood Jan 2020

Tools For Physicistsl Creating A Major-Based Foundational Course, Carol Hood

Q2S Enhancing Pedagogy

Pulling extensively from the recommendations from Phys21: Preparing Physics Students for 21st Century Careers1, a joint AAPT-APS committee report, we created a new semester course for all incoming physics majors, regardless of their math preparation. The Tools for Physicists course will attempt to set a foundation for what physicists do, why you would want to be one, and what you need to be successful.


Thermoelectric Porous Mof Based Hybrid Materials, Engelbert Redel, Helmut Baumgart Jan 2020

Thermoelectric Porous Mof Based Hybrid Materials, Engelbert Redel, Helmut Baumgart

Electrical & Computer Engineering Faculty Publications

Porous hybrid materials and MOF (Metal-Organic-Framework) films represent modern designer materials that exhibit many requirements of a near ideal and tunable future thermoelectric (TE) material. In contrast to traditional semiconducting bulk TE materials, porous hybrid MOF templates can be used to overcome some of the constraints of physics in bulk TE materials. These porous hybrid systems are amenable for simulation and modeling to design novel optimized electron-crystal phonon-glass materials with potentially very high ZT (figure of merit) numbers. Porous MOF and hybrid materials possess an ultra-low thermal conductivity, which can be further modulated by phonon engineering within their complex porous ...


Electron Tunneling And X-Ray Photoelectron Spectoscopy Studies Of The Superconductiong Properties Of Nitrogen-Doped Niobium Resonator Cavities, Eric M. Lechner, Basu Dev Oli, Junki Makita, Gianluigi Ciovati, Alex Gurevich, Maria Iavarone Jan 2020

Electron Tunneling And X-Ray Photoelectron Spectoscopy Studies Of The Superconductiong Properties Of Nitrogen-Doped Niobium Resonator Cavities, Eric M. Lechner, Basu Dev Oli, Junki Makita, Gianluigi Ciovati, Alex Gurevich, Maria Iavarone

Physics Faculty Publications

We use scanning tunneling microscopy (STM) and spectroscopy (STS), and x-ray photoelectron spectroscopy (XPS) to investigate the effect of nitrogen doping on the surface electronic and chemical structures of cutouts from superconducting Nb radio-frequency cavities. The goal of this work is to get insights into the fundamental physics and materials mechanisms behind the striking decrease of the surface resistance with the radio-frequency magnetic field, which has been observed on N-doped Nb cavities. Our XPS measurements reveal significantly more oxidized Nb 3d states and a thinner metallic suboxide layer on the N-doped Nb surfaces, which is also confirmed by tunneling spectroscopy ...


Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim Jan 2020

Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim

Physics Faculty Publications

We investigate thermodynamic properties of FeSe under in-plane magnetic fields using torque magnetometry, specific heat, and magnetocaloric measurements. Below the upper critical field Hc2, we observed the field induced anomalies at H1 ∼ 15 T and H2 ∼ 22 T near H ∥ ab and below a characteristic temperature T* ∼ 2 K. The transition magnetic fields H1 and H2 exhibit negligible dependence on both temperature and field orientation. This contrasts to the strong temperature and angle dependence of Hc2, suggesting that these anomalies are attributed to the field induced phase transitions, originating from the inherent spin-density-wave instability ...


Gold/Qds-Embedded-Ceria Nanoparticles: Optical Fluorescence Enhancement As A Quenching Sensor, Nader Shehata, Effat Samir, Ishac Kandas Jan 2020

Gold/Qds-Embedded-Ceria Nanoparticles: Optical Fluorescence Enhancement As A Quenching Sensor, Nader Shehata, Effat Samir, Ishac Kandas

Electrical & Computer Engineering Faculty Publications

This work focuses on improving the fluorescence intensity of cerium oxide (ceria) nanoparticles (NPs) through added plasmonic nanostructures. Ceria nanoparticles are fluorescent nanostructures which can emit visible fluorescence emissions under violet excitation. Here, we investigated different added plasmonic nanostructures, such as gold nanoparticles (Au NPs) and Cadmium sulfide/selenide quantum dots (CdS/CdSe QDs), to check the enhancement of fluorescence intensity emissions caused by ceria NPs. Different plasmonic resonances of both aforementioned nanostructures have been selected to develop optical coupling with both fluorescence excitation and emission wavelengths of ceria. In addition, different additions whether in-situ or post-synthesis have been investigated ...


Anomalous Stranski-Krastanov Growth Of (111)-Oriented Quantum Dots With Tunable Wetting Layer Thickness, Christopher F. Schuck, Simon K. Roy, Trent Garrett, Paul J. Simmonds Dec 2019

Anomalous Stranski-Krastanov Growth Of (111)-Oriented Quantum Dots With Tunable Wetting Layer Thickness, Christopher F. Schuck, Simon K. Roy, Trent Garrett, Paul J. Simmonds

Materials Science and Engineering Faculty Publications and Presentations

Driven by tensile strain, GaAs quantum dots (QDs) self-assemble on In0.52Al0.48As(111)A surfaces lattice-matched to InP substrates. In this study, we show that the tensile-strained self-assembly process for these GaAs(111)A QDs unexpectedly deviates from the well-known Stranski-Krastanov (SK) growth mode. Traditionally, QDs formed via the SK growth mode form on top of a flat wetting layer (WL) whose thickness is fixed. The inability to tune WL thickness has inhibited researchers’ attempts to fully control QD-WL interactions in these hybrid 0D-2D quantum systems. In contrast, using microscopy, spectroscopy, and computational modeling, we ...


9th Annual Postdoctoral Science Symposium, University Of Texas Md Anderson Cancer Center Postdoctoral Association Sep 2019

9th Annual Postdoctoral Science Symposium, University Of Texas Md Anderson Cancer Center Postdoctoral Association

MD Anderson Cancer Center Postdoctoral Association Annual Postdoctoral Science Symposium Abstracts

The mission of the Annual Postdoctoral Science Symposium (APSS) is to provide a platform for talented postdoctoral fellows throughout the Texas Medical Center to present their work to a wider audience. The MD Anderson Postdoctoral Association convened its inaugural Annual Postdoctoral Science Symposium (APSS) on August 4, 2011.

The APSS provides a professional venue for postdoctoral scientists to develop, clarify, and refine their research as a result of formal reviews and critiques of faculty and other postdoctoral scientists. Additionally, attendees discuss current research on a broad range of subjects while promoting academic interactions and enrichment and developing new collaborations.


Single-Neutron States In Titanium Isotopes, Jessica Nebel-Crosson Jul 2019

Single-Neutron States In Titanium Isotopes, Jessica Nebel-Crosson

Physics and Astronomy Summer Fellows

Current theory regarding the collective behavior of exotic nuclei systematically over-predicts the probabilities of exciting those collective states. The theory lacks any adjustable parameters, however, the model inputs are characteristics of single particle states which we are attempting to verify through neutron transfer into a 50Ti target.


Arduino Lab Assignments For Principles Of Physics Ii, William Baird, Jeffery Secrest Jul 2019

Arduino Lab Assignments For Principles Of Physics Ii, William Baird, Jeffery Secrest

Physics and Astronomy Ancillary Materials

This set of two Arduino assignments for Principles of Physics II includes an introductory assignment in exploring the Arduino's capabilities, followed by a lab assignment on data collection using the Arduino. These assignments were created as part of a Round Twelve Textbook Transformation Grant for Principles of Physics II.


Improving 3d Printed Prosthetics With Sensors And Motors, Rachel Zarin Jul 2019

Improving 3d Printed Prosthetics With Sensors And Motors, Rachel Zarin

Honors Projects

A 3D printed hand and arm prosthetic was created from the idea of adding bionic elements while keeping the cost low. It was designed based on existing models, desired functions, and materials available. A tilt sensor keeps the hand level, two motors move the wrist in two different directions, a limit switch signals the fingers to open and close, and another motor helps open and close the fingers. All sensors and motors were built on a circuit board, programmed using an Arduino, and powered by a battery. Other supporting materials include metal brackets, screws, guitar strings, elastic bands, small clamps ...


A Survey Of Dark Matter Candidates And Relations To Particle Physics And General Relativity, Tyler Martell May 2019

A Survey Of Dark Matter Candidates And Relations To Particle Physics And General Relativity, Tyler Martell

Honors Program Theses and Projects

Cosmological observations of certain galaxies suggest that the amount of known, measured matter accounted for by the Standard Model of Particle Physics (SM) in those systems is insufficient to account for galactic mechanics (orbital paths and velocities). These observations have led physicists to believe that either General Relativity (GR) is incomplete, or that there exist new sources of yet-to-be detected matter, that may or may not be consistent with SM, called dark matter. Neither GR nor the SM can alone be considered complete theories of the universe for GR is not quantum

mechanical and the SM does not include GR ...


Adding Student Video Projects To Physics Courses, David Abbott, Andrew Roberts, Dan L. Macisaac, Kathleen Falconer, Florian Genz, Stefan Hoffmann, Andre Bresges, Jeremias Weber Apr 2019

Adding Student Video Projects To Physics Courses, David Abbott, Andrew Roberts, Dan L. Macisaac, Kathleen Falconer, Florian Genz, Stefan Hoffmann, Andre Bresges, Jeremias Weber

Videos for Physics Teaching

Physics students have traditionally prepared many kinds of reports—laboratory, activity, project, and even book or article reports. Smartphones and YouTube videos are familiar cultural objects to current students, and our students use smartphone cameras to include photographs of apparatus, phenomena, hand-sketched figures, graphs, and mathematical equations in their physics reports. Here we present basic techniques for physics students to use smartphones and tablets to create short (< 5 min) end-of-semester video projects. Our students mainly use Apple Computer’s iPad1 tablets, but also other tablets and various smartphones. Finally we discuss appropriate instructor expectations and grading. Similar non-physics student video reporting efforts were reported using video cameras by Kearney,2 and Hechter and Guy.3


Physics 4900, David Maughan Apr 2019

Physics 4900, David Maughan

Physics Capstone Projects

More than a century has passed since Albert Einstein published his general theory of relativity. The theory has been tested many times experimentally, primarily in the relatively weak gravitational fields of the solar system [1,2]. More recently the first experimental results from the strong gravitational fields of two black holes have been measured in the form of gravitational waves, which are another prediction of general relativity. The 2017 Nobel prize in physics was awarded to Kip Thorne, Rainer Weiss, and Barry Barish for their role in the detection of gravitational waves. This year we have seen the first image ...


Specification-Based Grading Resources For Openstax College Physics (Ggc), Edward Forringer Apr 2019

Specification-Based Grading Resources For Openstax College Physics (Ggc), Edward Forringer

Physics and Astronomy Ancillary Materials

This collection of ancillary materials for Introductory Biology was created under a Round Eleven Mini-Grant for Ancillary Materials Creation and Revision. Included are the following resources to assist a faculty member in implementing specification grading in an introductory physics course using OpenStax College Physics:

  • Specification Grading Guide
  • Specification Documents
  • Quizzes
  • Practice Final Exam

Author's Description:

"Rather than grading each assignment with partial credit and then taking a weighted average of your assignments to find a grade, this course uses a set of course expectations called “specifications” (spec for short). Each spec has an associated quiz. Some specifications are designated ...


Ordered Growth Of Ferroelectric Diisopropylammonium-Bromide Microcrystals Through Slotted-Jar Growth And Lithographically Controlled Wetting, Andrew J. Fanning Mar 2019

Ordered Growth Of Ferroelectric Diisopropylammonium-Bromide Microcrystals Through Slotted-Jar Growth And Lithographically Controlled Wetting, Andrew J. Fanning

Honors Theses, University of Nebraska-Lincoln

Organic molecular ferroelectrics show promise for industry applications because of their switchable high spontaneous polarization value, mechanical flexibility, and cost-effectiveness. Since these materials, namely diisopropylammonium bromide, exhibit ferroelectricity only in tandem with a high level of crystallinity, novel methods must be explored in order to ensure that high levels of crystallinity are achieved. This project seeked to perfect the methods of Slotted Jar Growth and Lithographically Controlled Wetting (LCW). Slotted Jar Growth uses temperature driven solution saturation to grow crystals on a desired substrate. LCW drives the growth of microscopic diisopropylammonium bromide crystals, in their ferroelectric phase, through the use ...


Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji Jan 2019

Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji

Electrical & Computer Engineering Faculty Publications

Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg-1 at 2 mVs-1), higher surface capacitive contribution (75%), better stability and rate ...


Spectroscopy Of Neon For The Advanced Undergraduate Laboratory, H. C. Busch, M. B. Cooper, C. I. Sukenik Jan 2019

Spectroscopy Of Neon For The Advanced Undergraduate Laboratory, H. C. Busch, M. B. Cooper, C. I. Sukenik

Physics Faculty Publications

We describe a spectroscopy experiment, suitable for upper-division laboratory courses, that investigates saturated absorption spectroscopy and polarization spectroscopy in a neon discharge. Both experiments use nearly identical components, allowing students to explore both techniques in a single apparatus. Furthermore, because the wavelength of the laser is in the visible part of the spectrum (640 nm), the experiment is well-suited for students with limited experience in optical alignment. The labs nicely complement a course in atomic or plasma physics, provide students with the opportunity to gain important technical skills in the area of optics and lasers, and can provide an introduction ...


Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering Beyond Lowest Order, B. Wang, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato Jan 2019

Large Transverse Momentum In Semi-Inclusive Deeply Inelastic Scattering Beyond Lowest Order, B. Wang, J. O. Gonzalez-Hernandez, T. C. Rogers, N. Sato

Physics Faculty Publications

Motivated by recently observed tension between O(α2s) calculations of very large transverse momentum dependence in both semi-inclusive deep inelastic scattering and Drell-Yan scattering, we repeat the details of the calculation through an O(α2s) transversely differential cross section. The results confirm earlier calculations, and provide further support to the observation that tension exists with current parton distribution and fragmentation functions.


Instability Of Flux Flow And Production Of Vortex-Antivortex Pairs By Current-Driven Josephson Vortices In Layered Superconductors, Ahmad Sheikhzada, Alex Gurevich Jan 2019

Instability Of Flux Flow And Production Of Vortex-Antivortex Pairs By Current-Driven Josephson Vortices In Layered Superconductors, Ahmad Sheikhzada, Alex Gurevich

Physics Faculty Publications

We report numerical simulations of the nonlinear dynamics of Josephson vortices driven by strong dc currents in layered superconductors. Dynamic equations for interlayer phase differences in a stack of coupled superconducting layers were solved to calculate a drag coefficient η(J) of the vortex as a function of the perpendicular dc current density J. It is shown that Cherenkov radiation produced by a moving vortex causes significant radiation drag increasing η(v) at high vortex velocities v and striking instabilities of driven Josephson vortices moving faster than a terminal vc. The steady-state flux flow breaks down at ν > v ...