Physics Commons^™

Tidal Decay And Stable Roche-Lobe Overflow Of Short-Period Gaseous Exoplanets, Brian Jackson, Emily Jensen, Sarah Peacock, Phil Arras, Kaloyan Penev

Physics Faculty Publications and Presentations

Many gaseous exoplanets in short-period orbits are on the verge or are in the process of Roche-lobe overflow (RLO). Moreover, orbital stability analysis shows tides can drive many hot Jupiters to spiral inevitably toward their host stars. Thus, the coupled processes of orbital evolution and RLO likely shape the observed distribution of close-in exoplanets and may even be responsible for producing some of the short-period rocky planets. However, the exact outcome for an overflowing planet depends on its internal response to mass loss, and the accompanying orbital evolution can act to enhance or inhibit RLO. In this study, we apply …

Dust Devil Populations And Statistics, Ralph D. Lorenz, Brian K. Jackson

Physics Faculty Publications and Presentations

The highly-skewed diameter and pressure drop distributions of dust devils on Earth and Mars are noted, and challenges of presenting and comparing different types of observations are discussed. The widely- held view that Martian dust devils are larger than Earth's is critically-assessed: the question is confounded somewhat by different observation techniques, but some indication of a ~3x larger population on Mars is determined. The largest and most intense (in a relative pressure sense) devils recorded are on Mars, although the largest reported number density is on Earth. The difficulties of concepts used in the literature of 'average' diameter, pressure cross …

Magnetization Reversal In Ferromagnetic Spirals Via Domain Wall Motion, Ryan D. Schumm, Andrew Kunz

Physics Faculty Research and Publications

Domain wall dynamics have been investigated in a variety of ferromagnetic nanostructures for potential applications in logic, sensing, and recording. We present a combination of analytic and simulated results describing the reliable field driven motion of a domain wall through the arms of a ferromagnetic spiral nanowire. The spiral geometry is capable of taking advantage of the benefits of both straight and circular wires. Measurements of the in-plane components of the spirals' magnetization can be used to determine the angular location of the domain wall, impacting the magnetoresistive applications dependent on the domain wall location. The spirals' magnetization components are …

The Mid-Infrared Luminosity Evolution And Luminosity Function Of Quasars With Wise And Sdss, Jack Singal

Physics Faculty Publications

We determine the 22 μm luminosity evolution and luminosity function for quasars from a data set of over 20,000 objects obtained by combining flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey Explorer mid-infrared data. We apply methods developed in previous works to access the intrinsic population distributions non-parametrically, taking into account the truncations and correlations inherent in the data. We find that the population of quasars exhibits positive luminosity evolution with redshift in the mid-infrared, but with considerably less mid-infrared evolution than in the optical or radio bands. With the luminosity evolutions accounted for, we determine …

Observation Of Transverse Λ/Λ¯ Hyperon Polarization In E+E− Annihilation At Belle, A. Abdesselam Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

We report the first observation of the polarization of Λ/Λ¯ hyperons transverse to its production plane in e+e− annihilation. We observe a significant polarization that rises with the fractional energy carried by the hyperon as well as its transverse momentum. To define the production plane, we use the direction of the hyperon momentum together with either the thrust axis in the event or the momentum vector of a hadron in the opposite hemisphere. Furthermore, we investigate the contributions to the hyperon polarization from the feed-down from Σ0/Σ¯0 and Λ±c decays. This measurement uses a dataset of 800.4\~fb−1 collected by the …

Search For D^{0} Decays To Invisible Final States At Belle, Y.-T. Lai Et Al., D. Joffe, Ratnappuli L. Kulasiri

Faculty and Research Publications

We report the result from the first search for D0 decays to invisible final states. The analysis is performed on a data sample of 924  fb−1 collected at and near the Υ(4S) and Υ(5S) resonances with the Belle detector at the KEKB asymmetric-energy e+e− collider. The absolute branching fraction is determined using an inclusive D0 sample, obtained by fully reconstructing the rest of the particle system including the other charmed particle. No significant signal yield is observed and an upper limit of 9.4×10−5 is set on the branching fraction of D0 to invisible final states at 90% confidence level.

High Pressure Line Shapes Of The Rb D1 And D2 Lines For 4He And 3He Collisions, Wooddy S. Miller, Christopher A. Rice, Gordon D. Hager, Matthew D. Rotondaro, Hamid Berriche, Glen P. Perram

Faculty Publications

Line shapes for the Rb D₁ (5²S_1/2 ↔ 5²P_1/2) and D₂ (5²S_1/2 ↔ 5²P_3/2) transitions with ⁴He and ³He collisions at pressures of 500–15,000 Torr and temperatures of 333–533 K have been experimentally observed and compared to predictions from the Anderson–Talman theory. The ground X²Σ⁺_1/2 and excited A²Π_1/2, A²Π_3/2, and B²Σ⁺_1/2 potential energy surfaces required for the line shape predictions have been calculated using a one-electron …

Hard-Wall And Non-Uniform Lattice Monte Carlo Approaches To One-Dimensional Fermi Gases In A Harmonic Trap, Casey E. Berger, Joaquín E. Drut, William J. Porter

Physics: Faculty Publications

We present in detail two variants of the lattice Monte Carlo method aimed at tackling systems in external trapping potentials: a uniform-lattice approach with hard-wall boundary conditions, and a non-uniform Gauss–Hermite lattice approach. Using those two methods, we compute the ground-state energy and spatial density profile for systems of N=4–8 harmonically trapped fermions in one dimension. From the favorable comparison of both energies and density profiles (particularly in regions of low density), we conclude that the trapping potential is properly resolved by the hard-wall basis. Our work paves the way to higher dimensions and finite temperature analyses, as calculations with …

Hif Stabilization Weakens Primary Cilia, Andrew Resnick

Physics Faculty Publications

© 2016 Andrew Resnick. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Although solitary or sensory cilia are present in most cells of the body and their existence has been known since the sixties, very little is known about their functions. One suspected function is fluid flow sensing-physical bending of cilia produces an influx of Ca++, which can then result in a variety of activated signaling pathways. Defective cilia and ciliary-associated proteins have been …

Neutron Correlations In The Decay Of The First Excited State Of 11li, Jenna K. Smith, Thomas J. Baumann, Daniel Bazin, James Brown, Paul A. Deyoung, Nathan H. Frank, Michael D. Jones, Zack Kohley, Bryan A. Luther, B. S. Marks, Artemis Spyrou, Sharon L. Stephenson, Michael R. Thoennessen, Alexander S. Volya

Physics and Astronomy Faculty Publications

The decay of unbound excited ¹¹Li was measured after being populated by a two-proton removal from a ¹³B beam at 71 MeV/nucleon. Decay energy spectra and Jacobi plots were obtained from measurements of the momentum vectors of the ⁹Li fragment and neutrons. A resonance at an excitation energy of ∼1.2 MeV was observed. The kinematics of the decay are equally well fit by a simple dineutron-like model or a phase-space model that includes final state interactions. A sequential decay model can be excluded.

Target And Beam-Target Spin Asymmetries In Exclusive Π+ And Π− Electroproduction With 1.6- To 5.7-Gev Electrons, P. E. Bosted, A. S. Biselli, S. Careccia, G. Dodge, R. Fersch, N. Guler, S. E. Kuhn, J. Pierce, Y. Prok, X. Zheng, K. P. Adhikari, D. Adikaram, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, G. Asryan, H. Avakian, R. A. Badui, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, S. Boiarinov, W. J. Briscoe, S. Bültmann, V. D. Burkert, T. Cao, D. S. Carman, A. Celentano, Wesley P. Gohn

Physics and Astronomy Faculty Publications

Beam-target double-spin asymmetries and target single-spin asymmetries in exclusive π+ and quasiexclusive π− electroproduction were obtained from scattering of 1.6- to 5.7-GeV longitudinally polarized electrons from longitudinally polarized protons (for π+) and deuterons (for π−) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is 1.1 < W < 2.6 GeV and 0.05 < Q² < 5 GeV², with good angular coverage in the forward hemisphere. The asymmetry results were divided into approximately 40 000 kinematic bins for π+ from free protons and 15 000 bins for π− production from bound nucleons in the deuteron. The …

Results Of The Deepest All-Sky Survey For Continuous Gravitational Waves On Ligo S6 Data Running On The Einstein@Home Volunteer Distributed Computing Project, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the S6 LIGO science run. The search was possible thanks to the computing power provided by the volunteers of the Einstein@Home distributed computing project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population. At the frequency of best strain sensitivity, between 170.5 and 171 Hz we set a 90% confidence upper limit of 5.5 x 10^-25, while at the high end of …

The Rate Of Binary Black Hole Mergers Inferred From Advanced Ligo Observations Surrounding Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

A transient gravitational-wave signal, GW150914, was identified in the twin Advanced LIGO detectors on 2015 September 2015 at 09:50:45 UTC. To assess the implications of this discovery, the detectors remained in operation with unchanged configurations over a period of 39 days around the time of the signal. At the detection statistic threshold corresponding to that observed for GW150914, our search of the 16 days of simultaneous two-detector observational data is estimated to have a false-alarm rate (FAR) of < 4.9 x 10^-6 yr^-1, yielding a p-value for GW150914 of < 2 x 10^-7. Parameter estimation follow-up on this trigger identifies its source …

Fabrication And Characterization Of Graphite Oxide Based Field Effect Transistors For Non­ Enzymatic Glucose-Sensor Application, Khadija Said Rahman

Theses

Graphite-oxide based metal–oxide–semiconductor field-effect transistors (MOSFETs) were fabricated and used as glucose sensor. Herein, graphite-oxide was assembled between two planer electrical electrodes. The sensitivity of the sensor has been enhanced by adding copper (Cu) or silver (Ag) nanoparticles. The nanoparticles were produced by sputtering and inert gas condensation inside an ultra-high vacuum compatible system, and they were self-assembled on the graphite-oxide. The sensitivity of the sensor was increased by an order of magnitude when the silver nanoparticles were added. The sensitivity of each MOSFET was studied at different concentrations of non-enzymatic glucose for potential use in medical and industrial applications.

The Braking Index Of A Radio-Quiet Gamma-Ray Pulsar, C. J. Clark, H. J. Pletsch, J. Wu, L. Guillemot, F. Camilo, T. J. Johnson, M. Kerr, B. Allen, C. Aulbert, C. Beer, O. Bock, A. Cuellar, H. B. Eggenstein, H. Fehrmann, M. Kramer, B. Machenschalk, L. Nieder

Physics and Astronomy Faculty Publications and Presentations

We report the discovery and timing measurements of PSR J1208−6238, a young and highly magnetized gamma-ray pulsar, with a spin period of 440 ms. The pulsar was discovered in gamma-ray photon data from the Fermi Large Area Telescope (LAT) during a blind-search survey of unidentified LAT sources, running on the distributed volunteer computing system Einstein@Home. No radio pulsations were detected in dedicated follow-up searches with the Parkes radio telescope, with a flux density upper limit at 1369 MHz of 30 μJy. By timing this pulsar's gamma-ray pulsations, we measure its braking index over five years of LAT observations …

Investigation Of Electric Field–Induced Structural Changes At Fe-Doped Srtio3 Anode Interfaces By Second Harmonic Generation, David Ascienzo, Haochen Yuan, Steven Greenbaum, Thorsten J. Bayer, Russell A. Maier, Jian-Jun Wang, Clive A. Randall, Elizabeth C. Dickey, Haibin Zhao, Yuhang Ren

Publications and Research

We report on the detection of electric field–induced second harmonic generation (EFISHG) from the anode interfaces of reduced and oxidized Fe-doped SrTiO3 (Fe:STO) single crystals. For the reduced crystal, we observe steady enhancements of the susceptibility components as the imposed dc-voltage increases. The enhancements are attributed to a field-stabilized electrostriction, leading to Fe:Ti-O bond stretching and bending in Fe:Ti-O6 octahedra. For the oxidized crystal, no obvious structural changes are observed below 16 kV/cm. Above 16 kV/cm, a sharp enhancement of the susceptibilities occurs due to local electrostrictive deformations in response to oxygen vacancy migrations away from the anode. Differences between …

Cherenkov-Phase-Matched Nonlinear Optical Detection And Generation Of Terahertz Radiation Via Gaas With Metal-Coating, Ramon M. Delos Santos, Shinpei Ozawa, Valynn Magusara, Syougo Azuma, Anthony Tuico, Vernalyn Copa, Arnel Salvador, Kohji Yamamoto, Armando Somintac, Kazuyoshi Kurihara, Hideaki Kitahara, Masahiko Tani, Elmer Estacio

Physics Faculty Publications

Terahertz (THz) wave detection and emission via Cherenkov-phase-matched nonlinear optical effects at 1.55-μm optical wavelength were demonstrated using a GaAs with metal-coating (M-G-M) and bare GaAs as a reference sample in conjunction with a metallic tapered parallel-plate waveguide (TPPWG). The metal-coated GaAs is superior to the bare wafer both as a THz electro-optic detector and as an emitter. Significant improvements in the detection and emission efficiency were obtained by utilizing a metal-coating due to better confinement and lower loss of the THz waves propagating in the M-G-M compared with bare GaAs.

Femtosecond Pulse Trains Of Polychromatic Inverse Compton Γ-Rays From Designer Electron Beams Produced By Laser-Plasma Acceleration In Plasma Channels, Serge Y. Kalmykov, Isaac Ghebregziabher, X. Davoine, Remi Lehe, Agustin F. Lifschitz, Victor Malka, Bradley A. Shadwick

Serge Youri Kalmykov

Accordion Effect Revisited: Generation Of Comb-Like Electron Beams In Plasma Channels, Serge Y. Kalmykov, X. Davoine, Remi Lehe, Agustin F. Lifschitz, Bradley A. Shadwick

Serge Youri Kalmykov

Siuc Dark Site Observatory, Teresa M. Meyer Ms.

ASA Multidisciplinary Research Symposium

A joint venture between the SIUC Physics department, which houses the astronomy curriculum, and the Architecture department has begun the planning for the two upcoming total solar eclipses in 2017 and 2024.

Optical Detection Of Bilirubin, Hirotaka Nakagame

Von Braun Symposium Student Posters

No abstract provided.

Enhancing The Science Return Of Lunar Surface Studies: Analysis Of Rediscovered Data From Apollo 17'S Lunar Seismic Profiling Experiment, Deanna Phillips, Richard Miller

Von Braun Symposium Student Posters

No abstract provided.

The Intermediate-Line Region In Active Galactic Nuclei, T. P. Adhikari, A. Różańska, B. Czerny, K. Hryniewicz, Gary J. Ferland

Physics and Astronomy Faculty Publications

We show that the recently observed suppression of the gap between the broad-line region (BLR) and the narrow-line region (NLR) in some active galactic nuclei (AGNs) can be fully explained by an increase of the gas density in the emitting region. Our model predicts the formation of the intermediate-line region (ILR) that is observed in some Seyfert galaxies by the detection of emission lines with intermediate-velocity FWHM ~ 700–1200 km s⁻¹. These lines are believed to be originating from an ILR located somewhere between the BLR and NLR. As was previously proved, the apparent gap is assumed to …

Improving The Efficiency Of Gravitational Wave Detection, Jessica Page, Tyson Littenberg

Von Braun Symposium Student Posters

No abstract provided.

Examination Of The Nonlinear Dynamics And Possible Chaos Encryption In A Zeroth-Order Acousto-Optic Bragg Modulator With Feedback, Fares S. Almehmadi, Monish Ranjan Chatterjee

Monish R. Chatterjee

Zeroth-order chaos modulation in a Bragg cell is examined such that tracking problems due to spatial deflections of the first-order AO beam at the receiver may be avoided by switching to the undeviated zeroth-order beam.

Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed

Monish R. Chatterjee

The effects of turbulence on anisoplanatic imaging are often modeled through the use of a sequence of phase screens distributed along the optical path. We implement the split-step wave algorithm to examine turbulence-corrupted images.

Volume Component Analysis For Classification Of Lidar Data, Nina M. Varney, Vijayan K. Asari

Vijayan K. Asari

One of the most difficult challenges of working with LiDAR data is the large amount of data points that are produced. Analysing these large data sets is an extremely time consuming process. For this reason, automatic perception of LiDAR scenes is a growing area of research. Currently, most LiDAR feature extraction relies on geometrical features specific to the point cloud of interest. These geometrical features are scene-specific, and often rely on the scale and orientation of the object for classification. This paper proposes a robust method for reduced dimensionality feature extraction of 3D objects using a volume component analysis (VCA) …

Multiple Object Detection In Hyperspectral Imagery Using Spectral Fringe-Adjusted Joint Transform Correlator, Paheding Sidike, Vijayan K. Asari, Mohammad S. Alam

Vijayan K. Asari

Hyperspectral imaging (HSI) sensors provide plenty of spectral information to uniquely identify materials by their reflectance spectra, and this information has been effectively used for object detection and identification applications. Joint transform correlation (JTC) based object detection techniques in HSI have been proposed in the literatures, such as spectral fringe-adjusted joint transform correlation (SFJTC) and with its several improvements. However, to our knowledge, the SFJTC based techniques were designed to detect only similar patterns in hyperspectral data cube and not for dissimilar patterns. Thus, in this paper, a new deterministic object detection approach using SFJTC is proposed to perform multiple …

Directional Ringlet Intensity Feature Transform For Tracking, Evan Krieger, Paheding Sidike, Theus H. Aspiras, Vijayan K. Asari

Vijayan K. Asari

The challenges existing for current intensity-based histogram feature tracking methods in wide area motion imagery include object structural information distortions and background variations, such as different pavement or ground types. All of these challenges need to be met in order to have a robust object tracker, while attaining to be computed at an appropriate speed for real-time processing. To achieve this we propose a novel method, Directional Ringlet Intensity Feature Transform (DRIFT), that employs Kirsch kernel filtering and Gaussian ringlet feature mapping. We evaluated the DRIFT on two challenging datasets, namely Columbus Large Image Format (CLIF) and Large Area Image …

Histogram Of Oriented Phase (Hop): A New Descriptor Based On Phase Congruency, Hussin Ragb, Vijayan K. Asari

Vijayan K. Asari

In this paper we present a low level image descriptor called Histogram of Oriented Phase based on phase congruency concept and the Principal Component Analysis (PCA). Since the phase of the signal conveys more information regarding signal structure than the magnitude, the proposed descriptor can precisely identify and localize image features over the gradient based techniques, especially in the regions affected by illumination changes. The proposed features can be formed by extracting the phase congruency information for each pixel in the image with respect to its neighborhood. Histograms of the phase congruency values of the local regions in the image …