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2016

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Articles 1 - 30 of 881

Full-Text Articles in Physics

Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao Dec 2016

Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao

Faculty Publications

A simple and flexible optical system for generating electromagnetic or vector partially coherent sources or beams is presented. The alternative design controls field amplitude (beam shape), coherence, and polarization using only spatial light modulators. This improvement makes the apparatus simpler to construct and significantly increases the flexibility of vector partially coherent source generators by allowing many different types of sources to be produced without changing the physical setup. The system’s layout and theoretical foundations are thoroughly discussed. The utility and flexibility of the proposed system are demonstrated by producing a vector Schell-model and non-Schell-model source. The experimental results are compared …

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Searches For R -Parity-Violating Supersymmetry In Pp Collisions At Square Root Of S = 8 Tev In Final States With 0-4 Leptons, V. Khachatryan, A. M. Sirunyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva Dec 2016

Searches For R -Parity-Violating Supersymmetry In Pp Collisions At Square Root Of S = 8 Tev In Final States With 0-4 Leptons, V. Khachatryan, A. M. Sirunyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Results are presented from searches for R-parity-violating supersymmetry in events produced in pp collisions at s=8 TeV at the LHC. Final states with 0, 1, 2, or multiple leptons are considered independently. The analysis is performed on data collected by the CMS experiment corresponding to an integrated luminosity of 19.5 fb-1. No excesses of events above the standard model expectations are observed, and 95% confidence level limits are set on supersymmetric particle masses and production cross sections. The results are interpreted in models featuring R-parity-violating decays of the lightest supersymmetric particle, which in the studied scenarios can be either the …

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Mode-Sum Prescription For The Vacuum Polarization In Odd Dimensions, Peter Taylor, Cormac Breen Dec 2016

Mode-Sum Prescription For The Vacuum Polarization In Odd Dimensions, Peter Taylor, Cormac Breen

Articles

We present a new mode-sum regularization prescription for computing the vacuum polarization of a scalar field in static spherically-symmetric black hole spacetimes in odd dimensions. This is the first general and systematic approach to regularized vacuum polarization in higher dimensions. Remarkably, the regularization parameters can be computed in closed form in arbitrary dimensions and for arbitrary metric function $f(r)$. In fact, we show that in spite of the increasing severity and number of the divergences to be regularized, the method presented is mostly agnostic to the number of dimensions. Finally, as an explicit example of our method, we show plots …

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Probing Quantumness With Joint Continuous Measurements Of Non-Commuting Observables, Luis Pedro García-Pintos, Justin Dressel Dec 2016

Probing Quantumness With Joint Continuous Measurements Of Non-Commuting Observables, Luis Pedro García-Pintos, Justin Dressel

Mathematics, Physics, and Computer Science Faculty Articles and Research

We analyze the continuous measurement of two noncommuting observables for a qubit, and investigate whether the simultaneously observed noisy signals are consistent with the evolution of an equivalent classical system. Following the approach outlined by Leggett and Garg, we show that the readouts violate macrorealistic inequalities for arbitrarily short temporal correlations. Moreover, the derived inequalities are manifestly violated even in the absence of Hamiltonian evolution, unlike for Leggett-Garg inequalities that use a single continuous measurement. Such a violation should indicate the failure of at least one postulate of macrorealism: either physical quantities do not have well-defined values at all times …

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Advanced Dual Beam Optical Tweezers For Undergraduate Biophysics Research, Brian Daudelin Dec 2016

Advanced Dual Beam Optical Tweezers For Undergraduate Biophysics Research, Brian Daudelin

Honors Program Theses and Projects

Optical tweezing is a modern physics technique which allows us to use the radiation pressure provided from laser beams to trap very small microscopic particles. In the last two decades optical tweezers have been used extensively in biophysics and atomic physics to study the building blocks of our world on the cellular and quantum levels. Our goal is to construct a dual beam optical tweezers for future undergraduate biophysical research. In this thesis we discuss how the construction and assembly of the dual beam optical tweezers is done from start to finish. Construction consisted of assembling a polarization maintaining laser. …

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Measurement Of The Mass Of The Top Quark In Decays With A J/Ψ Meson In Pp Collisions At 8 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Dec 2016

Measurement Of The Mass Of The Top Quark In Decays With A J/Ψ Meson In Pp Collisions At 8 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A first measurement of the top quark mass in the decay channel t → (W → ℓν) (b → J/ψ + X → μ+μ− + X) is presented. The analysis uses events selected from the proton-proton collisions recorded by the CMS detector at the LHC at a center-of-mass energy of 8 TeV. The data correspond to an integrated luminosity of 19.7 fb−1, with 666 t t ¯ and single top quark candidate events containing a reconstructed J/ψ candidate decaying into an oppositely-charged muon pair. The mass of the (J/ψ + ℓ) system, where ℓ is an electron or a muon …

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Quantifying The Dna Binding Properties Of The Binuclear Ruthenium Complex Λλ-P, Nicholas Bryden Dec 2016

Quantifying The Dna Binding Properties Of The Binuclear Ruthenium Complex Λλ-P, Nicholas Bryden

Honors Program Theses and Projects

Threading intercalators are small molecules that bind to DNA by threading their side chains through the DNA bases to intercalate their middle planar section between the DNA base pairs. The high binding affinity and slow dissociation rates of threading intercalators have put them in the class of prospective anti-cancer drugs. In this study we explore the binding of a specific threading intercalator, a binuclear ruthenium complex ΛΛ-P (ΛΛ-[μ-bidppz(phen)4Ru2]4+) using optical tweezers. A single DNA molecule is held at a constant force and the small molecules are introduced to the system in various concentrations until equilibrium is achieved. Measurements of DNA …

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Generation Of Flower High-Order Poincaré Sphere Laser Beams From A Spatial Light Modulator, T. H. Lu, T. D. Huang, J. G. Wang, L. W. Wang, Robert R. Alfano Dec 2016

Generation Of Flower High-Order Poincaré Sphere Laser Beams From A Spatial Light Modulator, T. H. Lu, T. D. Huang, J. G. Wang, L. W. Wang, Robert R. Alfano

Publications and Research

We propose and experimentally demonstrate a new complex laser beam with inhomogeneous polarization distributions mapping onto high-order Poincaré spheres (HOPSs). The complex laser mode is achieved by superposition of Laguerre-Gaussian modes and manifests exotic flower-like localization on intensity and phase profiles. A simple optical system is used to generate a polarization-variant distribution on the complex laser mode by superposition of orthogonal circular polarizations with opposite topological charges. Numerical analyses of the polarization distribution are consistent with the experimental results. The novel flower HOPS beams can act as a new light source for photonic applications.

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Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown Dec 2016

Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown

Publications

The recent analytical of multi-layer analyses proposed by Sajjadi et al. (J Eng Math 84:73, 2014) (SHD14 therein) is solved numerically for atmospheric turbulent shear flows blowing over growing (or unsteady) Stokes (bimodal) water waves, of low-to-moderate steepness. For unsteady surface waves, the amplitude a(t)∝ekcita(t)∝ekcit, where kcikci is the wave growth factor, k is the wavenumber, and cici is the complex part of the wave phase speed, and thus, the waves begin to grow as more energy is transferred to them by the wind. This will then display the critical height to a point, where the thickness of the inner …

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Search For Dark Matter Particles In Proton-Proton Collisions At √S=8 Tev Using The Razor Variables, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Dec 2016

Search For Dark Matter Particles In Proton-Proton Collisions At √S=8 Tev Using The Razor Variables, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for dark matter particles directly produced in proton-proton collisions recorded by the CMS experiment at the LHC is presented. The data correspond to an integrated luminosity of 18.8 fb−1, at a center-of-mass energy of 8 TeV. The event selection requires at least two jets and no isolated leptons. The razor variables are used to quantify the transverse momentum balance in the jet momenta. The study is performed separately for events with and without jets originating from b quarks. The observed yields are consistent with the expected backgrounds and, depending on the nature of the production mechanism, dark matter …

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Effect Of Disorder On The Magnetic And Electronic Structure Of A Prospective Spin-Gapless Semiconductor Mncrval, P. Kharel, J. Herran, Pavel Lukashev, Y. Jin, J. Waybright, S. Gilbert, B, Staten, P. Gray, S. Valloppilly, Y. Huh, D. J. Sellmyer Dec 2016

Effect Of Disorder On The Magnetic And Electronic Structure Of A Prospective Spin-Gapless Semiconductor Mncrval, P. Kharel, J. Herran, Pavel Lukashev, Y. Jin, J. Waybright, S. Gilbert, B, Staten, P. Gray, S. Valloppilly, Y. Huh, D. J. Sellmyer

Faculty Publications

Recent discovery of a new class of materials, spin-gapless semiconductors (SGS), has attracted considerable attention in the last few years, primarily due to potential applications in the emerging field of spin-based electronics (spintronics). Here, we investigate structural, electronic, and magnetic properties of one potential SGS compound, MnCrVAl, using various experimental and theoretical techniques. Our calculations show that this material exhibits ≈ 0.5 eV band gap for the majority-spin states, while for the minority-spin it is nearly gapless. The calculated magnetic moment for the completely ordered structure is 2.9 µB/f.u., which is different from our experimentally measured value of …

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Search For Dark Matter In Proton-Proton Collisions At 8 Tev With Missing Transverse Momentum And Vector Boson Tagged Jets, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Dec 2016

Search For Dark Matter In Proton-Proton Collisions At 8 Tev With Missing Transverse Momentum And Vector Boson Tagged Jets, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is presented for an excess of events with large missing transverse momentum in association with at least one highly energetic jet, in a data sample of proton-proton collisions at a centre-of-mass energy of 8 TeV. The data correspond to an integrated luminosity of 19.7 fb−1 collected by the CMS experiment at the LHC. The results are interpreted using a set of simplified models for the production of dark matter via a scalar, pseudoscalar, vector, or axial vector mediator. Additional sensitivity is achieved by tagging events consistent with the jets originating from a hadronically decaying vector boson. This search …

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Real-Space Mean-Field Theory Of A Spin-1 Bose Gas In Synthetic Dimensions, Hilary M. Hurst, Justin H. Wilson, J. H. Pixley, I. B. Spielman, Stefan S. Natu Dec 2016

Real-Space Mean-Field Theory Of A Spin-1 Bose Gas In Synthetic Dimensions, Hilary M. Hurst, Justin H. Wilson, J. H. Pixley, I. B. Spielman, Stefan S. Natu

Faculty Research, Scholarly, and Creative Activity

The internal degrees of freedom provided by ultracold atoms give a route for realizing higher dimensional physics in systems with limited spatial dimensions. Non-spatial degrees of freedom in these systems are dubbed "synthetic dimensions". This connection is useful from an experimental standpoint but complicated by the fact that interactions alter the condensate ground state. Here we use the Gross-Pitaevskii equation to study ground state properties of a spin-1 Bose gas under the combined influence of an optical lattice, spin-orbit coupling, and interactions at the mean field level. The associated phases depend on the sign of the spin-dependent interaction parameter and …

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Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan Dec 2016

Sdss-Iv Manga – The Spatially Resolved Transition From Star Formation To Quiescence, Francesco Belfiore, Roberto Maiolino, Claudia Maraston, Eric Emsellem, Matthew A. Bershady, Karen L. Masters, Dmitry Bizyaev, Médéric Boquien, Joel R. Brownstein, Kevin Bundy, Aleksandar M. Diamond-Stanic, Niv Drory, Timothy M. Heckman, David R. Law, Olena Malanushenko, Audrey Oravetz, Kaike Pan, Alexandre Roman-Lopes, Daniel Thomas, Anne-Marie Weijmans, Kyle B. Westfall, Renbin Yan

Physics and Astronomy Faculty Publications

Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionization emission-line regions (LIERs) in local galaxies result from photoionization by hot evolved stars, not active galactic nuclei, hence tracing galactic region hosting old stellar population where, despite the presence of ionized gas, star formation is no longer occurring. LIERs are ubiquitous in both quiescent galaxies and in the central regions of galaxies where star formation takes place at larger radii. We refer to these two classes of galaxies as extended LIER (eLIER) and central LIER (cLIER) galaxies, respectively. cLIERs are late-type galaxies primarily spread across the green …

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Studies Of Inclusive Four-Jet Production With Two B-Tagged Jets In Proton-Proton Collisions At 7 Tev, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva Dec 2016

Studies Of Inclusive Four-Jet Production With Two B-Tagged Jets In Proton-Proton Collisions At 7 Tev, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Measurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 pb-1. The cross section is measured as a function of the jet transverse momentum for pT>20 GeV, and of the jet pseudorapidity for |η|<2.4 (b jets), 4.7 (untagged jets). The correlations in azimuthal angle and pT between the jets are also studied. The inclusive cross section is measured to be σ(pp→2b+2j+X)=69±3(stat)±24(syst) nb. The η and pT distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions. © 2016 CERN.

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Search For Long-Lived Charged Particles In Proton-Proton Collisions At √S = 13 Tev, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva Dec 2016

Search For Long-Lived Charged Particles In Proton-Proton Collisions At √S = 13 Tev, V. Khachatryan, A. M. Sirunyan, A. R. Tumasyan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Daniel Noonan, Tuhin S. Roy, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Results are presented of a search for heavy stable charged particles produced in proton-proton collisions at √s = 13 TeV using a data sample corresponding to an integrated luminosity of 2.5 fb-1 collected in 2015 with the CMS detector at the CERN LHC. The search is conducted using signatures of anomalously high energy deposits in the silicon tracker and long time-of-flight measurements by the muon system. The data are consistent with the expected background, and upper limits are set on the cross sections for production of long-lived gluinos, top squarks, tau sleptons, and leptonlike long-lived fermions. These upper limits are …

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Linear Feedback Stabilization For A Continuously Monitored Qubit, Taylor Lee Patti, A. Chantasri, Justin Dressel, A. N. Jordan Dec 2016

Linear Feedback Stabilization For A Continuously Monitored Qubit, Taylor Lee Patti, A. Chantasri, Justin Dressel, A. N. Jordan

Student Scholar Symposium Abstracts and Posters

In quantum mechanics, standard or strong measurement approaches generally result in the collapse of an ensemble of wavefunctions into a stochastic mixture of eigenstates. On the other hand, continuous or weak measurements have the propensity to dynamically control the evolution of quantum states over time, guiding the trajectory of the state into non-trivial superpositions and maintaining state purity. This kind of measurement-induced state steering is of great theoretical and experimental interest for the harnessing of quantum bits or "qubits", which are the fundamental unit of the emerging quantum computer. We explore continuous measurement-based quantum state stabilization through linear feedback control …

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Search For New Physics In Final States With Two Opposite-Sign, Same-Flavor Leptons, Jets, And Missing Transverse Momentum In Pp Collisions At √S = 13 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Dec 2016

Search For New Physics In Final States With Two Opposite-Sign, Same-Flavor Leptons, Jets, And Missing Transverse Momentum In Pp Collisions At √S = 13 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is presented for physics beyond the standard model in final states with two opposite-sign, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 2.3 fb−1 of proton-proton collisions at s=13 TeV collected with the CMS detector at the LHC in 2015. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. Both search modes use several event categories in order to increase the sensitivity to new physics. These categories are based on the rapidity of the …

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Structural Reinforcement Through Liquid Encapsulation, Alin Cristian Chipara, Peter Samora Owuor, Sanjit Bhowmick, Gustavo Brunetto, S. A. Syed Asif, Mircea Chipara, Robert Vajtai, Jun Lou, Douglas S. Galvao, Chandra Sekhar Tiwary Dec 2016

Structural Reinforcement Through Liquid Encapsulation, Alin Cristian Chipara, Peter Samora Owuor, Sanjit Bhowmick, Gustavo Brunetto, S. A. Syed Asif, Mircea Chipara, Robert Vajtai, Jun Lou, Douglas S. Galvao, Chandra Sekhar Tiwary

Physics and Astronomy Faculty Publications and Presentations

The liquid inside a solid material is one of the most common composite materials in nature. The interface between solid–liquid plays an important role in unique deformation. Here, model systems of two polymers (polydimethylsiloxane–polyvinylidenefluoride) are used to make sphere of solid with liquid inside it.

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De Haas-Van Alphen Study Of Role Of 4f Electrons In Antiferromagnetic Cezn₁₁ As Compared To Its Nonmagnetic Analog Lazn₁₁, S. F. Blake, Halyna Hodovanets, A. Mccollam, S. L. Bud'ko, P. C. Canfield, A. I. Coldea Dec 2016

De Haas-Van Alphen Study Of Role Of 4f Electrons In Antiferromagnetic Cezn₁₁ As Compared To Its Nonmagnetic Analog Lazn₁₁, S. F. Blake, Halyna Hodovanets, A. Mccollam, S. L. Bud'ko, P. C. Canfield, A. I. Coldea

Physics Faculty Research & Creative Works

We present a de Haas-van Alphen study of the Fermi surface of the low-temperature antiferromagnet CeZn11 and its nonmagnetic analog LaZn11, measured by torque magnetometry up to fields of 33T and at temperatures down to 320mK. Both systems possess similar de Haas-van Alphen frequencies, with three clear sets of features -- ranging from 50T to 4kT -- corresponding to three bands of a complex Fermi surface, with an expected fourth band also seen weakly in CeZn11. The effective masses of the charge carriers are very light ( < 1me) in LaZn11 but a factor …

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Use Of Solid N2 Surfaces In Metastable Particle Detection, Wladyslaw Kedzierski, J. W. Mcconkey Dec 2016

Use Of Solid N2 Surfaces In Metastable Particle Detection, Wladyslaw Kedzierski, J. W. Mcconkey

Physics Publications

A novel detector is described in which solid nitrogen at 17 K is used as the most significant element. Metastable particles impinge on this element and immediately transfer their internal energy to the solid nitrogen producing photons, via excimer formation or otherwise, whose wavelength depends on the metastable being detected and the energy transfer process. The performance of the instrument for the detection of atomic oxygen and molecular nitrogen metastables is discussed.

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Transport And Optical Conductivity In The Hubbard Model: A High-Temperature Expansion Perspective, Edward Perepelitsky, Andrew Galatas, Jernej Mravlje, Rok Žitko, Ehsan Khatami, B. Shastry, Antoine Georges Dec 2016

Transport And Optical Conductivity In The Hubbard Model: A High-Temperature Expansion Perspective, Edward Perepelitsky, Andrew Galatas, Jernej Mravlje, Rok Žitko, Ehsan Khatami, B. Shastry, Antoine Georges

Faculty Publications

We derive analytical expressions for the spectral moments of the dynamical response functions of the Hubbard model using the high-temperature series expansion. We consider generic dimension d as well as the infinite-d limit, arbitrary electron density n, and both finite and infinite repulsion U. We use moment-reconstruction methods to obtain the one-electron spectral function, the self-energy, and the optical conductivity. They are all smooth functions at high temperature and, at large U, they are featureless with characteristic widths of the order of the lattice hopping parameter t. In the infinite-d limit, we compare the series expansion results with accurate numerical …

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Dielectric Analysis Of Aqueous Poly(L-Glutamic Acid) And Poly-L-(Glutamic Acid4, Tyrosine1) Solutions At High Frequencies From Capacitance Measurements, Jorge Monreal, Tatiana Eggers, Manh-Huong Phan Dec 2016

Dielectric Analysis Of Aqueous Poly(L-Glutamic Acid) And Poly-L-(Glutamic Acid4, Tyrosine1) Solutions At High Frequencies From Capacitance Measurements, Jorge Monreal, Tatiana Eggers, Manh-Huong Phan

Physics Faculty Publications

A new parallel-plate capacitor fixture has been designed and successfully used to measure dielectric loss of polyelectrolyte solutions with volumes as low as droplets of 13–26 μL. It is particularly useful when studying polypeptides that are either high-cost or can be synthesized only in limited quantities. The ease with which the fixture can be used to obtain preliminary dielectric loss data yields savings in time and cost. In this study capacitance measurements were performed in a wide range of frequencies between 1 and 800 MHz using an Agilent 4191RF Impedance Analyzer. Accuracy of measurements was carefully examined through a comparison …

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Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell Dec 2016

Coursenetworking And Community: Linking Online Discussion Networks And Course Success, Adrienne L. Traxler, Andrew Gavrin, Rebecca Lindell

Physics Faculty Publications

Large introductory science courses are isolating for many students, and reducing this isolation is an important factor for student retention in college. Active learning courses often build community among students as an explicit goal, but many commuter or non-traditional students have limited on-campus time. Online discussion forums provide one tool for engaging students with each other outside of class time. This study uses social network analysis with forum data from an introductory physics course to examine students' positions in the class discussion network and link it to their final course grades. We find that, contrary to expectations, there is no …

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A Laboratory Facility To Study Gas-Aerosol-Cloud Interactions In A Turbulent Environment: The Π Chamber, K. Chang, J. Bench, M. Brege, Will Cantrell, K. Chandrakar, David Ciochetto, Claudio Mazzoleni, Lynn Mazzoleni, Dennis Niedermeier, R. A. Shaw Dec 2016

A Laboratory Facility To Study Gas-Aerosol-Cloud Interactions In A Turbulent Environment: The Π Chamber, K. Chang, J. Bench, M. Brege, Will Cantrell, K. Chandrakar, David Ciochetto, Claudio Mazzoleni, Lynn Mazzoleni, Dennis Niedermeier, R. A. Shaw

Department of Physics Publications

A detailed understanding of interactions of aerosols, cloud droplets/ice crystals, and trace gases within the atmosphere is of prime importance for an accurate understanding of Earth’s weather and climate. One aspect that remains especially vexing is that clouds are ubiquitously turbulent, and therefore thermodynamic and compositional variables, such as water vapor supersaturation, fluctuate in space and time. With these problems in mind, a multiphase, turbulent reaction chamber—called the Π chamber because of the internal volume of 3.14 m3 with the cylindrical insert installed—has been developed. It is capable of pressures ranging from 1,000 to –60 hPa and can sustain …

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Identity‐Based Schemes For A Secured Big Data And Cloud Ict Framework In Smart Grid System, Feng Ye, Yi Qian, Rose Qingyang Hu Dec 2016

Identity‐Based Schemes For A Secured Big Data And Cloud Ict Framework In Smart Grid System, Feng Ye, Yi Qian, Rose Qingyang Hu

Electrical and Computer Engineering Faculty Publications

Smart grid is an intelligent cyber physical system (CPS). The CPS generates a massive amount of data for efficient grid operation. In this paper, a big data‐driven, cloud‐based information and communication technology (ICT) framework for smart grid CPS is proposed. The proposed ICT framework deploys hybrid cloud servers to enhance scalability and reliability of smart grid communication infrastructure. Because the data in the ICT framework contains much privacy of customers and important data for automated controlling, the security of data transmission must be ensured. In order to secure the communications over the Internet in the system, identity‐based schemes are proposed …

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Plasma Processes And Polymers Third Special Issue On Plasma And Cancer, Mounir Laroussi, Annemie Bogaerts, Nazir Barekzi Dec 2016

Plasma Processes And Polymers Third Special Issue On Plasma And Cancer, Mounir Laroussi, Annemie Bogaerts, Nazir Barekzi

Electrical & Computer Engineering Faculty Publications

(First paragraph) This issue of Plasma Processes and Polymers is the third in a series on the applications of low temperature plasma (LTP) against cancer, or “plasma oncology.” The papers in this issue are inspired from the talks given at the third International Workshop on Plasma for Cancer Treatment (IWPCT) which took place on April 11–12, 2016 in Washington, DC, USA. IWPCT is an international workshop that was created in 2014 as a venue to share cutting edge plasma oncology research. The first IWPCT was held in Washington DC, under the co-chairmanship of Prof. Mounir Laroussi (Old Dominion University) and …

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Computational Fluid Dynamics Is Key To Better Flying Aircraft, Nihad E. Daidzic Dec 2016

Computational Fluid Dynamics Is Key To Better Flying Aircraft, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

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What Determines The Fate Of Rising Parcels In A Heterogeneous Environment?, Maren Brast, Roel A.J. Neggers, Thijs Heus Dec 2016

What Determines The Fate Of Rising Parcels In A Heterogeneous Environment?, Maren Brast, Roel A.J. Neggers, Thijs Heus

Physics Faculty Publications

© 2016. The Authors. We investigate the potential impact of the local environment on rising parcels in a convective boundary layer. To this end, we use data from an LES simulation of a shallow convective cloud field to feed a parcel model with a range of different local environments, representative of the heterogeneous environment inside a shallow cumulus cloud layer. With this method we can study the statistics of an ensemble of rising parcels, but also the behavior of individual parcels. Through the use of a heterogeneous environment, the interactions between different parcels are indirectly represented. The method, despite its …

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Cgils Phase 2 Les Intercomparison Of Response Of Subtropical Marine Low Cloud Regimes To Co2 Quadrupling And A Cmip3 Composite Forcing Change, Peter N. Blossey, Christopher S. Bretherton, Anning Cheng, Satoshi Endo, Thijs Heus, Adrian P. Lock, Johan J. Van Der Dussen Dec 2016

Cgils Phase 2 Les Intercomparison Of Response Of Subtropical Marine Low Cloud Regimes To Co2 Quadrupling And A Cmip3 Composite Forcing Change, Peter N. Blossey, Christopher S. Bretherton, Anning Cheng, Satoshi Endo, Thijs Heus, Adrian P. Lock, Johan J. Van Der Dussen

Physics Faculty Publications

© 2016. The Authors. Phase 1 of the CGILS large-eddy simulation (LES) intercomparison is extended to understand if subtropical marine boundary-layer clouds respond to idealized climate perturbations consistently in six LES models. Here the responses to quadrupled carbon dioxide (“fast adjustment”) and to a composite climate perturbation representative of CMIP3 multimodel mean 2×CO2 near-equilibrium conditions are analyzed. As in Phase 1, the LES is run to equilibrium using specified steady summertime forcings representative of three locations in the Northeast Pacific Ocean in shallow well-mixed stratocumulus, decoupled stratocumulus, and shallow cumulus cloud regimes. The results are generally consistent with a single-LES …

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