Physics Commons^™

Highly Efficient And Exact Method For Parallelization Of Grid-Based Algorithms And Its Implementation In Delphi, Chuan Li, Lin Li, Jie Zhang, Emil Alexov

Publications

The Gauss–Seidel (GS) method is a standard iterative numerical method widely used to solve a system of equations and, in general, is more efficient comparing to other iterative methods, such as the Jacobi method. However, standard implementation of the GS method restricts its utilization in parallel computing due to its requirement of using updated neighboring values (i.e., in current iteration) as soon as they are available. Here, we report an efficient and exact (not requiring assumptions) method to parallelize iterations and to reduce the computational time as a linear/nearly linear function of the number of processes or computing units. In …

An Item Response Curves Analysis Of The Force Concept Inventory, Gary A. Morris, Nathan Harshman, Lee Branum-Martin, Eric Mazur, Taha Mzoughi, Stephen D. Baker

Faculty and Research Publications

Several years ago, we introduced the idea of item response curves (IRC), a simplistic form of item response theory (IRT), to the physics education research community as a way to examine item performance on diagnostic instruments such as the Force Concept Inventory (FCI). We noted that a full-blown analysis using IRT would be a next logical step, which several authors have since taken. In this paper, we show that our simple approach not only yields similar conclusions in the analysis of the performance of items on the FCI to the more sophisticated and complex IRT analyses but also permits additional …

Analysis Of Cornell Electron-Positron Storage Ring Test Accelerator's Double Slit Visual Beam Size Monitor, Robert Campbell

Physics

In the past year, a double slit interferometer was installed to measure the horizontal beam size in the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) at Cornell University in Ithaca, NY. To better understand the systematics of this device, a replica of the CesrTA instrument was assembled at California Polytechnic State University San Luis Obispo. From the prototype, it was found that the device will produce a calculated beam size that agrees with measurements as long as it is optimized with the proper double slits for a small range of beam sizes.

Analysis Of The Spectra Of Trivalent Erbium In Multiple Sites Of Hexagonal Aluminum Nitride, John B. Gruber, Ulrich Vetter, Gary W. Burdick, Zachery D. Fleishman, Larry D. Merkle, Takashi Taniguchi, Yuan Xiaoli, Takashi Sekiguchi, Daniel Jurgens, Hans Hofsass

Faculty Publications

The 12 K cathodoluminescence spectra of Er3+ doped into single crystals of aluminum nitride (2H-AlN) in the hexagonal phase are reported between 320 nm and 775 nm. The emission spectra represent transitions from the lower Stark level of 2P(3/2) to the Stark levels of the 4I(15/2), 4I(13/2), 4I(11/2), 4I(9/2), 4F(9/2), and 4S(3/2) multiplet manifolds of Er3+(4f(11)). Emission spectra from 4S(3/2) to 4I(15/2) are also reported. All observed strong line emission are accounted for in terms of two principle sites, denoted site "a" and site "b", with a few line spectra attributed to additional sites. A parameterized Hamiltonian that includes the …

Search For A T-Odd, P-Even Triple Correlation In Neutron Decay, T. E. Chupp, R. L. Cooper, K. P. Coulter, S. J. Freedman, B. K. Fujikawa, A. Garcia, Gordon L. Jones, H. P. Mumm, J. S. Nico, A. K. Thompson, C. A. Trull, F. E. Wietfeldt, J. F. Wilkerson

Articles

Background: Time-reversal-invariance violation, or equivalently CP violation, may explain the observed cosmological baryon asymmetry as well as indicate physics beyond the Standard Model. In the decay of polarized neutrons, the triple correlation D⟨⃗Jn⟩/Jn⋅(⃗βe׈pν) is a parity-even, time-reversal-odd observable that is uniquely sensitive to the relative phase of the axial-vector amplitude with respect to the vector amplitude. The triple correlation is also sensitive to possible contributions from scalar and tensor amplitudes. Final-state effects contribute to D at the level of 10−5 and can be calculated with a precision of 1% or better.

Purpose: We have improved the sensitivity to T-odd, P-even …

Velocity-Selective Direct Frequency-Comb Spectroscopy Of Atomic Vapors, Jason E. Stalnaker, S. L. Chen, M. E. Rowan, K. Nguyen, T. Pradhananga, C. A. Palm, Derek F. Jackson Kimball

Faculty & Staff Scholarship

We present an experimental and theoretical investigation of two-photon direct frequency-comb spectroscopy performed through velocity-selective excitation. In particular, we explore the effect of repetition rate on the [formula] two-photon transitions excited in a rubidium atomic vapor cell. The transitions occur via stepwise excitation through the [formula] states by use of the direct output of an optical frequency comb. Experiments were performed with two different frequency combs, one with a repetition rate of [formula] MHz and one with a repetition rate of [formula] MHz. The experimental spectra are compared to each other and to a theoretical model.

Enhanced Asymmetry In Few-Cycle Attosecond Pulse Ionization Of He In The Vicinity Of Autoionizing Resonances, Jean Marcel Ngoko Djiokap, S. X. Hu, Wei-Chao Jiang, Liang-You Peng, Anthony F. Starace

Anthony F. Starace Publications

By solving the two-active-electron, time-dependent Schrödinger equation in its full dimensionality, we investigate the carrier-envelope phase (CEP) dependence of single ionization of He to the He⁺(1s) state triggered by an intense few-cycle attosecond pulse with carrier frequency ω corresponding to the energy ћω = 36 eV. Effects of electron correlations are probed by comparing projections of the final state of the two-electron wave packet onto field-free highly correlated Jacobi matrix wave functions with projections onto uncorrelated Coulomb wave functions. Significant differences are found in the vicinity of autoionizing resonances. Owing to the broad bandwidths of our 115 and …

Continuous Single-Column Model Evaluation At A Permanent Meteorological Supersite, Roel A.J. Neggers, A. Pier Siebesma, Thijs Heus

Physics Faculty Publications

Uncertainties in numerical predictions of weather and climate are often linked to the representation of unresolved processes that act relatively quickly compared to the resolved general circulation. These processes include turbulence, convection, clouds, and radiation. Single-column model (SCM) simulation of idealized cases and the subsequent evaluation against large-eddy simulation (LES) results has become an often used and relied on method to obtain insight at process level into the behavior of such parameterization schemes; benefits of SCM simulation are the enhanced model transparency and the high computational efficiency. Although this approach has achieved demonstrable success, some shortcomings have been identified; among …

Turbulent Concentration Diffusion In Multiphase Flow, John D. Ramshaw

Physics Faculty Publications and Presentations

In multifluid multiphase flow models, the velocity of each phase is determined by its own momentum equation, which is coupled to the other phases by pairwise interphase drag forces proportional to velocity differences. When the drag coefficients are large, the phase velocities become nearly equal and the relative motion of the phases becomes diffusional rather than inertial. The multifluid momentum equations then reduce to a single momentum equation for the mixture and a system of linear relations that determine the small residual velocity differences between the phases. We derive such diffusional relations in a very general form that applies to …

Erratum: Search For Gravitational Waves From Binary Black Hole Inspiral, Merger, And Ringdown (Physical Review D - Particles, Fields, Gravitation And Cosmology (2011) 83 (122005)), J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Since the publication we have discovered two errors in the calculation of upper limits on binary black hole (BBH) coalescence rates inferred from the nondetection of gravitational waves. The errors caused systematic biases of opposite signs and different sizes in the 90% confidence rate limits; when errors are corrected, the resulting limits are a factor 3 to 5 smaller than those quoted. Here we give a brief description of the errors and report their impacts on the upper limit results.

Ion-Lithium Collision Dynamics Studied With A Laser-Cooled In-Ring Target, Daniel Fischer, Dominik Globig, Johannes Goullon, Manfred Grieser, Renate Hubele, Vitor L B D De Jesus, Aditya H. Kelkar, Aaron C. Laforge, H. Lindenblatt, Deepankar S. Misra, B. Najjari, Katharina R. Schneider, Michael Schulz, Martin Sell, Xincheng Wang

Physics Faculty Research & Creative Works

We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi,' is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In the inaugural experiment on collisions with 1.5MeV/amu O8 ⁺-Li the pure ionization of the valence electron as well as the ionization-excitation of the lithium target was investigated.

Non-Fermi Liquid Transport And "Universal" Ratios In Quantum Griffiths Phases, David Nozadze, Thomas Vojta

Physics Faculty Research & Creative Works

We use the semi-classical Boltzmann equation to investigate transport properties such as electrical resistivity, thermal resistivity, thermopower, and the Peltier coefficient of disordered metals close to an antiferromagnetic quantum phase transition. In the quantum Griffiths phase, the electrons are scattered by spin-fluctuations in the rare regions. This leads to singular temperature dependencies not just at the quantum critical point, but in the entire Griffiths phase. We show that the resulting non-universal power-laws in transport properties are controlled by the same Griffiths exponent λ which governs the thermodynamics. λ takes the value zero at the quantum critical point and increases throughout …

Review Of Treatment Of Error In Second Language Student Writing By Dana R. Ferris, Melanie C. González

Melanie González

Utilization Of A Tropospheric-Stratospheric Lidar System To Study Mountain Induced Gravity Waves Over Jenny Jump State Forest, Anthony Teti

Theses

Gravity waves are a dominant driver of the middle and lower atmospheric circulation. Yet such waves have been difficult to study due to their inherent small spatial and temporal scales and synoptic occurrence, and thus require advanced experimental systems. In this thesis first results are presented from a newly constructed tropospheric-stratospheric lidar operating at the New Jersey Institute of Technology-United Astronomy Clubs of New Jersey site in Jenny Jump State Forest in northwest New Jersey. The system utilizes a 4-W 532-nm Nd:YAG laser transmitter and a 4-inch telescope receiver to collect backscattered photons from the lower atmosphere in order to …

Nanoscale Surface Patterning And Applications: Using Top-Down Patterning Methods To Aid Bottom-Up Fabrication, Anthony Craig Pearson

Theses and Dissertations

Bottom-up self-assembly can be used to create structures with sub-20 nm feature sizes or materials with advanced electrical properties. Here I demonstrate processes to enable such self-assembling systems including block copolymers and DNA origami, to be integrated into nanoelectronic devices. Additionally, I present a method which utilizes the high stability and electrical conductivity of graphene, which is a material formed using a bottom-up growth process, to create archival data storage devices. Specifically, I show a technique using block copolymer micelle lithography to fabricate arrays of 5 nm gold nanoparticles, which are chemically modified with a single-stranded DNA molecule and used …

Magnetism Of Zno Nanoparticles: Dependence On Crystallite Size And Surfactant Coating, Aaron P. Thurber, Geoffrey L. Beausoleil Ii, Gordon A. Alanko, Joshua Anghel, Michael S. Jones, Lydia M. Johnson, Jianhui Zhang, Charles B. Hanna, Dmitri A. Tenne, Alex Punnoose

Charles Hanna

Many recent reports on magnetism in otherwise nonmagnetic oxides have demonstrated that nanoparticle size, surfactant coating, or doping with magnetic ions produces room-temperature ferromagnetism. Specifically, ZnO has been argued to be a room-temperature ferromagnet through all three of these methods in various experimental studies. For this reason, we have prepared a series of 1% Fe doped ZnO nanoparticle samples using a single forced hydrolysis co-precipitation synthesis method from the same precursors, while varying size (6 – 15 nm) and surface coating concentration to study the combined effects of these two parameters. Size was controlled by modifying the water concentration. Surfactant …

Size, Surface Structure, And Doping Effects On Ferromagnetism In Sno2, Gordon A. Alanko, Aaron Thurber, Charles Hanna, Alex Punnoose

Charles Hanna

The effects of crystallite size, surface structure, and dopants on the magnetic properties of semiconducting oxides are highly controversial. In this work, Fe:SnO₂ nanoparticles were prepared by four wet-chemical methods, with Fe concentration varying from 0% to 20%. Analysis confirmed pure single-phase cassiterite with a crystallite size of 2.6 ± 0.1 nm that decreased with increasing. Fe% doped substitutionally as Fe³⁺. Pure SnO₂ showed highly reproducible weak magnetization that varied significantly with synthesis method. Interestingly, doping SnO₂ with Fe < 2.5% produced enhanced magnetic moments in all syntheses; the maximum of 1.6 × 10⁻⁴ µ_B/Fe ion at 0.1% Fe doping was much larger than the 2.6 × …

Smectic Pores And Defect Cores, Elisabetta A. Masumoto, Randall D. Kamien, Christian Santangelo

Christian Santangelo

Riemann's minimal surfaces, a one-parameter family of minimal surfaces, describe a bicontinuous lamellar system with pores connecting alternating layers. We demonstrate explicitly that Riemann's minimal surfaces are composed of a nonlinear sum of two oppositely handed helicoids.

Molecular Dynamics Studies Of Water Flow In Carbon Nanotubes, Alexander D. Marshall

Electronic Thesis and Dissertation Repository

We present classical molecular dynamics (MD) simulations providing insight into the behaviour of water. We focus on confined water, the properties of which are often significantly different from the properties of bulk water.

First, we performed several simulations investigating the handling of long-range interactions in GROMACS [1], a MD simulation package. Selection of simulation protocols such as handling of long-range interactions is often overlooked, sometimes to the significant detriment of the final result [2, 3, 4]. Ensuring that the chosen simulation protocols are appropriate is a critical step in computer simulation.

Second, we performed MD simulations where water flowed between …

Molecule For Electronics: A Myriad Of Opportunities Comes With Daunting Challenges, Ranjit Pati

Department of Physics Publications

Since the invention of Integrated Circuit (IC) in 1958, we have seen an unprecedented growth in Si-based electronics industry; ICs are currently used in almost all electronic gadgets. However, it is now very much clear that this era of growth we have been witnessing for the last five decades will soon hit the brick wall, once the transistor size reaches the physical limit of miniaturization.