Physics Commons^™

Response To Griffiths, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

"First of all, I would like to thank Prof. Griffith for his comments. The exchange has reminded me of the series of letters that appeared in Physics Today following the publication of an article by Chandralekha Singh, Mario Belloni, and Wolfgang Christian on improving the teaching of undergraduate quantum mechanics (see http://ptonline.aip.org/ journals/doc/PHTOAD-ft/vol_60/iss_3/8_1.shtml). In those responses, both Griffiths and Travis Norsen argued that students’ understanding of quantum mechanics would be vastly improved if they were taught more about the foundations of quantum theory, and I wholeheartedly agree with that sentiment. The thing is, Griffiths argued vociferously that this should be …

Review Of Elegance And Enigma: The Quantum Interviews, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

A review of Elegance and Enigma: The Quantum Interviews, edited by Maximilian Schlosshauer.

Review Of The Mathematical Language Of Quantum Theory: From Uncertainty To Entanglement, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

A book review of The Mathematical Language of Quantum Theory: From Uncertainty to Entanglement by Teiko Heinosaari and Mario Ziman.

Pbr, Epr, And All That Jazz, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

"In the past couple of months, the quantum foundations world has been abuzz about a new preprint entitled "The Quantum State Cannot be Interpreted Statistically" by Matt Pusey, Jon Barrett and Terry Rudolph (henceforth known as PBR). Since I wrote a blog post explaining the result, I have been inundated with more correspondence from scientists and more requests for comment from science journalists than at any other point in my career. Reaction to the result amongst quantum researchers has been mixed, with many people reacting negatively to the title, which can be misinterpreted as an attack on the Born rule. …

Fast Super-Resolution With Affine Motion Using An Adaptive Wiener Filter And Its Application To Airborne Imaging, Russell C. Hardie, Kenneth J. Barnard, Raúl Ordóñez

Electrical and Computer Engineering Faculty Publications

Fast nonuniform interpolation based super-resolution (SR) has traditionally been limited to applications with translational interframe motion. This is in part because such methods are based on an underlying assumption that the warping and blurring components in the observation model commute. For translational motion this is the case, but it is not true in general. This presents a problem for applications such as airborne imaging where translation may be insufficient. Here we present a new Fourier domain analysis to show that, for many image systems, an affine warping model with limited zoom and shear approximately commutes with the point spread function …

A Model Of So-Called "Zebra" Emissions In Solar Flare Radio Burst Continua, R. A. Treumann, R. Nakamura, W. Baumjohann

Dartmouth Scholarship

A simple mechanism for the generation of elec- tromagnetic “Zebra” pattern emissions is proposed. “Zebra” bursts are regularly spaced narrow-band radio emissions on the otherwise broadband radio continuum emitted by the ac- tive solar corona. The mechanism is based on the generation of an ion-ring distribution in a magnetic mirror geometry in the presence of a properly directed field-aligned electric po- tential field. Such ion-rings or ion-conics are well known from magnetospheric observations. Under coronal condi- tions they may become weakly relativistic. In this case the ion-cyclotron maser generates a number of electromagnetic ion-cyclotron harmonics which modulate the electron maser …

Exploring Methods For Earthquake Prediction: The Effects Of Water On The Flow Of Stress-Activated Electric Currents In Igneous Rocks, Aaron M. Jahoda, Friedemann T. Freund

STAR Program Research Presentations

Much of the devastation and damage of earthquakes can be attributed to the fact that they occur suddenly and without much warning, which limits the ability of people to evacuate and/or properly prepare. One method, however, that might be used to predict seismic events is the generation of electric currents in rocks when stresses are applied. It is observed in this research that the application of direct force onto samples of igneous rock causes the rocks to generate a measurable current, which is attributed to positive-hole charges moving within the oxygen sub-lattice. Because large and changing forces are acted upon …

Variable Renewable Energy In Modeling Climate Change Mitigation Scenarios, Falko Ueckerdt, Robert J. Brecha, Gunnar Luderer, Patrick Sullivan, Eva Schmid, Nico Bauer, Diana Böttger

Physics Faculty Publications

This paper addresses the issue of how to account for short‐term temporal variability of renewable energy sources and power demand in long‐term climate change mitigation scenarios in energy‐economic models. An approach that captures in a stylized way the major challenges to the integration of variable renewable energy sources into power systems has been developed. As a first application this approach has been introduced to REMIND‐D, a hybrid energy‐economy model of Germany. An approximation of the residual load duration curve is implemented. The approximating function endogenously changes depending on the penetration and mix of variable renewable power. The approach can thus …

Super-Resolution For Imagery From Integrated Microgrid Polarimeters, Russell C. Hardie, Daniel A. Lemaster, Bradley Michael Ratliff

Electrical and Computer Engineering Faculty Publications

Imagery from microgrid polarimeters is obtained by using a mosaic of pixel-wise micropolarizers on a focal plane array (FPA). Each distinct polarization image is obtained by subsampling the full FPA image. Thus, the effective pixel pitch for each polarization channel is increased and the sampling frequency is decreased. As a result, aliasing artifacts from such undersampling can corrupt the true polarization content of the scene. Here we present the first multi-channel multi-frame super-resolution (SR) algorithms designed specifically for the problem of image restoration in microgrid polarization imagers. These SR algorithms can be used to address aliasing and other degradations, without …

Logistic Curves, Extraction Costs And The Effective Size Of Oil Resources, Robert J. Brecha

Physics Faculty Publications

The size of potential fossil fuel resources is an issue of perennial interest and controversy. Fundamentally, there appears to be a conflict in interpretation of available data for both past and future extraction histories. As fossil-fuel prices rose dramatically over the past several years, the question of resources once again became acute. In this paper we concentrate on conventional and non-conventional oil resources and make four main points, with the overarching theme that one can determine an effective oil resource that represents significantly less availability for consumption than usually posited by tallying resources in place.

First, looking at oil production …

Prioritizing Investment In Residential Energy Efficiency And Renewable Energy: A Case Study For The U.S. Midwest, Robert J. Brecha, Austin Mitchell, Kevin P. Hallinan, J. Kelly Kissock

Physics Faculty Publications

Residential building energy use is an important contributor to greenhouse gas emissions and in the United States represents about 20% of total energy consumption. A number of previous macro-scale studies of residential energy consumption and energy-efficiency improvements are mainly concerned with national or international aggregate potential savings. In this paper we look into the details of how a collection of specific homes in one region might reduce energy consumption and carbon emissions, with particular attention given to some practical limits to what can be achieved by upgrading the existing residential building stock. Using a simple model of residential, single-family home …

Sbs-Based Radar True Time Delay, Mark Bashkansky, David Walker, Armen Gulian, Michael Steiner

Mathematics, Physics, and Computer Science Faculty Articles and Research

Stimulated Brillouin scattering (SBS) based slow light is considered for application to squint-free (true time delay) steering of phased array radar antennae. Results are presented on true time delay radar requirements, including delay precision and bandwidth. We experimentally investigated the level of delay precision that exists in actual slow-light systems (based on Brillouin scattering). The practical use of SBS to meet the necessary requirements for radar use is discussed.

Magnetism Of Cluster-Deposited Y–Co Nanoparticles, Balamuruga Balamurugan, Ralph Skomski, Xingzhong Li, V. R. Shah, George C. Hadjipanayis, Jeffrey E. Shield, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Nanoparticles of YCo₂, YCo_3, and YCo₅ are produced by cluster-deposition and investigated both structurally and magnetically. The nanoparticles have sizes of less than 10 nm and are superparamagnetic at 300 K, irrespective of stoichiometry. As-produced nanoparticles exhibit disordered structures with magnetic properties differing from those of the bulk particles. The temperature-dependent magnetization curves of the nanoparticles reveal blocking temperatures from 110 to 250 K, depending on stoichiometry. The magnetic anisotropy constant K₁ of disordered YCo₅ nanoparticles of 7.8 nm in size is 3.5×10⁶ergs/cm³, higher than those of the disordered YCo …

Structure And Magnetism Of Mnau Nanoclusters, X. Wei, Damien Le Roy, Ralph Skomski, Xingzhong Li, Zhiguang Sun, Jeffrey E. Shield, M. J. Kramer, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Equiatomic MnAu clusters with average sizes of 4 and 10 nm are produced by inert-gas condensation. As-produced clusters are used to form both dense cluster films and films with clusters embedded in a W matrix with a cluster volume fraction of 25%. Both structure and magnetism are size-dependent. Structural analysis of the 10 nm clusters indicate a distorted tetragonal body-centered cubic structure with lattice parameters a=0.315 and c=0.329 nm. The 4 nm clusters have a partially ordered tetragonal L10 structure with lattice parameters a=0.410 nm and c=0.395 nm. Magnetic properties of the clusters show evidence at …

In Memoriam: Robert Katz (1917–2011), M. P. R. Waligorski, Francis A. Cucinotta

Robert Katz Publications

Bob Katz will be well remembered for his enthusiasm and strong personality. In a scientific dispute, few indeed could match his wit or his sense of humor or survive the cutting logic of his arguments. To those who had appreciation for his science and his personality, he was truly a great scientist and a master teacher. There are many people around the world who will remember Bob Katz for what he offered them and for the way he showed them what truth in science is.

The Katz Model, developed at that time for solid-state detectors and for cell cultures, relates …

Novel Tissue Mimicking Materials For High Frequency Breast Ultrasound Phantoms, Louise Cannon, Andrew Fagan, Jacinta Browne

Articles

The development and acoustical characterisation of a range of novel agar-based tissue mimicking material (TMMs) for use in clinically relevant, quality assurance (QA) and anthropomorphic breast phantoms are presented. The novel agar-based TMMs described in this study are based on a comprehensive, systematic variation of the ingredients in the International Electrotechnical Commission (IEC) TMM. A novel, solid fat-mimicking material was also developed and acoustically characterised. Acoustical characterisation was carried out using an in-house scanning acoustic macroscope at low (7.5 MHz) and high frequencies (20 MHz), using the pulse-echo insertion technique. The speeds of sound range from 1490 to 1570 m. …

Diffusive Transport Enhanced By Thermal Velocity Fluctuations, Alejandro Garcia, A. Donev, A. De La Fuente, J. B. Bell

Faculty Publications

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. We find good agreement between a simple fluctuating hydrodynamics theory and particle and finite-volume simulations. The enhancement of the diffusive transport depends on the system size L and grows as ln⁡(L/L0) in quasi-two-dimensional systems, while in three dimensions it scales as L0-1-L-1, where L0 is a reference length. Our results demonstrate that fluctuations play an important role in the hydrodynamics of small-scale systems.

Establishing Building Recommissioning Priorities And Potential Energy Savings From Utility Energy Data, Kevin P. Hallinan, Philip Brodrick, Jessica Northridge, J. Kelly Kissock, Robert J. Brecha

Physics Faculty Publications

An energy reduction program for commercial buildings is implemented for a SW Ohio natural gas utility. The aim of this study is to demonstrate that historical utility data for individual building customers, along with knowledge of pertinent building information (square footage, year built, number of floors, height of floors, wall construction type, and use type) available in county auditor databases, could be used to identify the best candidate buildings for recommissioning in terms of energy savings and simple payback. A study is completed for all natural gas customers of a utility in Montgomery and Clinton counties in Ohio. A total …

Modeling And Tuning Of Musical Percussive Beams, Eric Laukkanen

Summer Research

Standard vibraphone bars consist of aluminum beams which are traditionally tuned with an arched undercut, for the purpose of aligning the musical overtones harmonically. The acoustical effect of various progressions of undercuts on aluminum bars was studied using both an aluminum bar and a finite element computer model. The spectral signature of the aluminum bar was examined with a spectrum analyzer, and the corresponding eigenmodes were imaged with an electronic speckle pattern interferometer. These methods were used to analyze the changes in natural frequencies of the bar as matter was removed from various locations. Additionally, the aural character of each …

Targeting Residential Energy Reduction For City Utilities Using Historical Electrical Utility Data And Readily Available Building Data, Kevin P. Hallinan, J. Kelly Kissock, Robert J. Brecha, Austin Mitchell

Physics Faculty Publications

Energy use data for the eight-year period 2003–2010 was analyzed for over 1200 single family residences in Village of Yellow Springs, Ohio. Electricity, natural gas, residential building, and weather databases are merged to permit determination of the energy intensity of each home in the village. The energy use intensity for each home is disaggregated into weather independent and weather dependent electric and natural gas use. This use is compared to typical baseline, cooling, and heating energy use for the region. From this comparison, priority homes are identified for energy reduction investment. Collective potential low cost energy reduction is estimated for …

Resonant Photoemission Of Rare Earth Doped Gan Thin Films, S. R. Mchale, J. W. Mcclory, J. C. Petrosky, J. Wu, R. Palai, Yaroslav B. Losovyj, Peter A. Dowben

Peter Dowben Publications

The 4d → 4f Fano resonances for various rare earth doped GaN thin films (RE = Gd, Er, Yb) were investigated using synchrotron photoemission spectroscopy. The resonant photoemission Fano profiles show that the major Gd and Er rare earth 4f weight is at about 5–6 eV below the valence band maximum, similar to the 4f weights in the valence band of many other rare earth doped semiconductors. For Yb, there is very little resonant enhancement of the valence band of Yb doped GaN, consistent with a largely 4f¹⁴ occupancy.

Schottky Barrier Formation At The Au To Rare Earth Doped Gan Thin Film Interface, S. R. Mchale, J. W. Mcclory, J. C. Petrosky, J. Wu, R. Palai, Yaroslav B. Losovyj, Peter A. Dowben

Peter Dowben Publications

The Schottky barriers formed at the interface between gold and various rare earth doped GaN thin films (RE = Yb, Er, Gd) were investigated in situ using synchrotron photoemission spectroscopy. The resultant Schottky barrier heights were measured as 1.68 ± 0.1 eV (Yb:GaN), 1.64 ± 0.1 eV (Er:GaN), and 1.33 ± 0.1 eV (Gd:GaN). We find compelling evidence that thin layers of gold do not wet and uniformly cover the GaN surface, even with rare earth doping of the GaN. Furthermore, the trend of the Schottky barrier heights follows the trend of the rare earth metal work function.

Mesoscale Flux-Closure Domain Formation In Single-Crystal Batio3, R. G.P. Mcquaid, L. J. Mcgilly, Pankaj Sharma, Alexei Gruverman, J. M. Gregg

Alexei Gruverman Publications

Over 60 years ago, Charles Kittel predicted that quadrant domains should spontaneously form in small ferromagnetic platelets. He expected that the direction of magnetization within each quadrant should lie parallel to the platelet surface, minimizing demagnetizing fields, and that magnetic moments should be configured into an overall closed loop, or flux-closure arrangement. Although now a ubiquitous observation in ferromagnets, obvious flux-closure patterns have been somewhat elusive in ferroelectric materials. This is despite the analogous behaviour between these two ferroic subgroups and the recent prediction of dipole closure states by atomistic simulations research. Here we show Piezoresponse Force Microscopy images of …

Heat Recovery Mechanism In The Excitation Of Radiative Polaritons By Broadband Infrared Radiation In Thin Oxide Films, Anita J. Vincent-Johnson, Kyle A. Vasquez, John E. Bridstrup, Andrew E. Masters, Xiaofeng Hu, Giovanna Scarel

Department of Physics and Astronomy - Faculty Scholarship

This work probes radiative polaritons in thin oxide layers as a mean to capture and absorb broadband infrared radiation and transform it into heat. A heat recovery mechanism, based on the Seebeck effect, is used as the tool of the investigation. Heat production challenges the current understanding which views the excitation of radiative polaritons as only accompanied by the emission of electromagnetic radiation. The heat recovery mechanism presented here can inspire the design of infrared energy harvesting devices, similar to photovoltaic cells, and other devices to convert energy from a wide range of the electromagnetic radiation spectrum using thermoelectric power …

Pulsed Laser Deposition Of Graphite Counter Electrodes For Dye-Sensitized Solar Cells, Krishna P. Acharya, Himal Khatri, Sylvain Marsillac, Bruno Ullrich, Pavel Anzenbacher, Mikhail Zamkov

Electrical & Computer Engineering Faculty Publications

We report on pulsed laser deposition of graphite onto flexible plastic and conductive glass substrates for use as a counter electrode in dye-sensitized solar cells. The efficiency of as-prepared graphite electrodes was tested using CdS-sensitized solar cell architecture resulting in external quantum efficiency comparable to that of conventional platinum counter electrodes. This work highlights the possibility of using pulsed laser deposited graphite as a low-cost alternative to platinum, which could be fabricated both on flexible and rigid substrates.

Upgrade To The Pierre Auger Cosmic Ray Observatory's Lidar System, Emily B. Petermann

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

The Pierre Auger Cosmic Ray Observatory currently operates four elastic lidar systems in order to characterize the atmospheric aerosol content above the observatory. The atmospheric information gained by the lidar system is then used in the calibration of the observatory’s four fluorescence detectors. Currently the four lidars in operation are unable to accurately determine the aerosol content below a distance of 1 km. A project is currently underway to upgrade the current lidar system by adding an additional detector to each of the existing lidar systems. The considered designs for this upgrade and the initial results from the upgrade prototype …

Analysis Of An All-Optical Sbs Avalanche Detector, D. Walker, M. Steiner, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

Seeding Brillouin scattering with a sufficiently efficient source of coherent phonons has the potential to produce energy-sensitive photon detectors. Based on this idea, we propose and analyze some possible designs for such a detector.

Dynamical Theory Calculations Of Spin-Echo Resolved Grazing-Incidence Scattering From A Diffraction Grating, Rana Ashkar, P. Stonaha, A. L. Washington, V. R. Shah, M. R. Fitzsimmons, B. Maranville, C. F. Majkrzak, W. T. Lee, W. L. Schaich, Roger Pynn

Nebraska Center for Materials and Nanoscience: Faculty Publications

Neutrons scattered or reflected from a diffraction grating are subject to a periodic potential analogous to the potential experienced by electrons within a crystal. Hence, the wavefunction of the neutrons can be expanded in terms of Bloch waves and a dynamical theory can be applied to interpret the scattering phenomenon. In this paper, a dynamical theory is used to calculate the results of neutron spin-echo resolved grazing-incidence scattering (SERGIS) from a silicon diffraction grating with a rectangular profile. The calculations are compared with SERGIS measurements made on the same grating at two neutron sources: a pulsed source and a continuous …

A Hybrid Particle-Continuum Method For Hydrodynamics Of Complex Fluids, Alejandro Garcia, A. Donev, J. B. Bell, B. Alder

Faculty Publications

A previously developed hybrid particle-continuum method [J. B. Bell, A. Garcia, and S. A. Williams, Multiscale Model. Simul., 6 (2008), pp. 1256–1280] is generalized to dense fluids and two- and three-dimensional flows. The scheme couples an explicit fluctuating compressible Navier–Stokes solver with the isotropic direct simulation Monte Carlo (DSMC) particle method [A. Donev, A. L. Garcia, and B. J. Alder, J. Stat. Mech. Theory Exp., 2009 (2009), article P11008]. To achieve bidirectional dynamic coupling between the particle (microscale) and continuum (macroscale) regions, the continuum solver provides state-based boundary conditions to the particle subdomain, while the particle solver provides flux-based boundary …

Computational Fluctuating Fluid Dynamics, Alejandro Garcia, J. B. Bell, S. Williams

Faculty Publications

This paper describes the extension of a recently developed numerical solver for the Landau-Lifshitz Navier-Stokes (LLNS) equations to binary mixtures in three dimensions. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by using white-noise fluxes. These stochastic PDEs are more complicated in three dimensions due to the tensorial form of the correlations for the stochastic fluxes and in mixtures due to couplings of energy and concentration fluxes (e.g., Soret effect). We present various numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate good agreement with theoretical results and molecular simulation