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Articles 1441 - 1470 of 1948

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On The Classical Limits Of Physics, Valia Allori, Nino Zanghì Jan 2009

On The Classical Limits Of Physics, Valia Allori, Nino Zanghì

Faculty Articles, Papers, and Other Scholarship

Contrary to the widespread belief, the problem of the emergence of classical mechanics from quantum mechanics is still open. In spite of many results of the standard approach, it is not yet clear how to explain within standard quantum mechanics the classical motion of macroscopic bodies. In this paper, we shall formulate the classical limit as a scaling limit in terms of an adimensional parameter ε. We shall take the first steps toward a comprehensive understanding of the classical limit, analyzing special cases of classical behavior in the framework of a precise formulation of quantum mechanics called Bohmian mechanics which …


Forked:A Demonstration Of Physics Realism In Augmented Reality, David Beaney, Brian Mac Namee Jan 2009

Forked:A Demonstration Of Physics Realism In Augmented Reality, David Beaney, Brian Mac Namee

Conference papers

In making fully immersive augmented reality (AR) applications, real and virtual objects will have to be seen to physically interact together in a realistic and believable way. This paper describes Forked! a system that has been developed to show how physical interactions between real and virtual objects can be simulated re- alistically and believably through appropriate use of a physics en- gine. The system allows users control a robotic forklift to manipu- late virtual crates in an AR environment. The paper also describes a evaluation experiment in which it is shown that the physical inter- actions between the forklift and …


Precise Measurement Of The Neutron Magnetic Form Factor Gnm In The Few-Gev² Region, Clas Collaboration, J. Lachniet, H. Bagdasaryan, S. Bültmann, N. Kalantarians, G. E. Dodge, T. A. Forest, G. Gavalian, C. E. Hyde-Wright, A. Klien, S. E. Kuhn, M. R. Niroula, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Zhang Jan 2009

Precise Measurement Of The Neutron Magnetic Form Factor Gnm In The Few-Gev² Region, Clas Collaboration, J. Lachniet, H. Bagdasaryan, S. Bültmann, N. Kalantarians, G. E. Dodge, T. A. Forest, G. Gavalian, C. E. Hyde-Wright, A. Klien, S. E. Kuhn, M. R. Niroula, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q2 = 1.0–4.8  GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data


Electroproduction Of P Π⁺Π⁻ Off Protons At 0.2 < Q² < 0.6 Gev² And 1.3 < W < 1.57 Gev With The Clas Detector, M. J. Amaryan, H. Baghdasaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde, W. Kim, A. Klein, F. J. Klein, A. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, Et Al., Clas Collaboration Jan 2009

Electroproduction Of P Π⁺Π⁻ Off Protons At 0.2 < Q² < 0.6 Gev² And 1.3 < W < 1.57 Gev With The Clas Detector, M. J. Amaryan, H. Baghdasaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde, W. Kim, A. Klein, F. J. Klein, A. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep → e'pπ+π-. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2 < Q2 < 0.6 GeV2 and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q2 covered by the measurements. A phenomenological analysis of the data allowed …


Conformal Kernel For The Next-To-Leading-Order Bfkl Equation In 𝒩 = 4 Super Yang-Mills Theory, Ian Balitsky, Giovanni A. Chirilli Jan 2009

Conformal Kernel For The Next-To-Leading-Order Bfkl Equation In 𝒩 = 4 Super Yang-Mills Theory, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

Using the requirement of Möbius invariance of 𝒩 = 4 super Yang-Mills amplitudes in the Regge limit, we restore the explicit form of the conformal next-to-leading-order Balitsky-Fadin-Kuraev-Lipatov (BFKL) kernel out of the eigenvalues known from the forward next-to-leading-order BFKL result.


Backscatter And Attenuation Characterization Of Ventricular Myocardium, Allyson Gibson Jan 2009

Backscatter And Attenuation Characterization Of Ventricular Myocardium, Allyson Gibson

All Theses and Dissertations (ETDs)

This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium. In this Dissertation, integrated backscatter and attenuation analyses were performed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The …


Properties Of Neutron Star Critical Collapses, Mew-Bing Wan Jan 2009

Properties Of Neutron Star Critical Collapses, Mew-Bing Wan

All Theses and Dissertations (ETDs)

Critical phenomena in gravitational collapse opened a new mathematical vista into the theory of general relativity and may ultimately entail fundamental physical implication in the astrophysical realm, especially in gravitational collapse scenarios. However, at present, the dynamics of critical phenomena in realistic astrophysical gravitational collapse scenarios are still largely unknown. My thesis seeks to understand the properties of the neutron star critical solution, understand the properties of the threshold in the solution space of the Einstein field equations between the black hole and a neutron star phases, and clarify the implication these results on realistic astrophysical scenarios. We develop a …


Formation Of Even-Numbered Hydrogen Cluster Cations In Ultracold Helium Droplets, S. Jaksch, A. Mauracher, A. Bacher, S. Denifl, F. Ferreira De Silva, H. Schoebel, Olof E. Echt, T. D. Maerk, M. Probst, D. K. Bohme, P. Scheier Dec 2008

Formation Of Even-Numbered Hydrogen Cluster Cations In Ultracold Helium Droplets, S. Jaksch, A. Mauracher, A. Bacher, S. Denifl, F. Ferreira De Silva, H. Schoebel, Olof E. Echt, T. D. Maerk, M. Probst, D. K. Bohme, P. Scheier

Physics & Astronomy

Neutral hydrogen clusters are grown in ultracold helium nanodroplets by successive pickup of hydrogen molecules. Even-numbered hydrogen cluster cations are observed upon electron-impact ionization with and without attached helium atoms and in addition to the familiar odd-numbered H(n)(+). The helium matrix affects the fragmentation dynamics that usually lead to the formation of overwhelmingly odd-numbered H(n)(+). The use of high-resolution mass spectrometry allows the unambiguous identification of even-numbered H(n)(+) up to n congruent to 120 by their mass excess that distinguishes them from He(n)(+), mixed He(m)H(n)(+), and background ions. The large range in size of these hydrogen cluster ions is unprecedented, …


Coherent Control Of Nanomagnet Dynamics Via Ultrafast Spin Torque Pulses, Samir Garzon, Longfei Ye, Richard A. Webb, Thomas M. Crawford, Mark Covington, Shehzaad Kaka Nov 2008

Coherent Control Of Nanomagnet Dynamics Via Ultrafast Spin Torque Pulses, Samir Garzon, Longfei Ye, Richard A. Webb, Thomas M. Crawford, Mark Covington, Shehzaad Kaka

Faculty Publications

We demonstrate reliable manipulation of the magnetization dynamics of a precessing nanomagnet by precisely controlling the spin transfer torque on the subnanosecond time scale. Using a simple pulse shaping scheme consisting of two ultrafast spin torque pulses with variable amplitudes and delay, we demonstrate coherent control over the precessional orbits and the ability to tune the switching probability of a nanomagnet at room temperature and 77 K. Our measurements suggest that appropriately shaped spin transfer can be used to efficiently manipulate the orientation of a free layer nanomagnet, thus providing an alternative for spin torque driven spintronic devices.


A Catalog Of Outer Ejecta Knots In The Cassiopeia A Supernova Remnant, Molly C. Hammell, Robert A. Fesen Nov 2008

A Catalog Of Outer Ejecta Knots In The Cassiopeia A Supernova Remnant, Molly C. Hammell, Robert A. Fesen

Dartmouth Scholarship

Hubble Space Telescope images of the core-collapse supernova remnant Cassiopeia A are used to identify high-velocity knots of ejecta located outside the remnant's main emission shell of expanding debris. These ejecta fragments are found near or ahead of the remnant's forward shock front and mostly lie from 120'' to 300'' in radial distance from the remnant's center of expansion. Filter flux ratios when correlated with published spectra show that these knots can be divided into three emission classes: (1) knots dominated by [N II] λλ6548, 6583 emissions, (2) knots dominated by [O II] λλ7319, 7330 emissions, and (3) …


Contributions To Random Energy Models., Nabin Kumar Jana Dr. Oct 2008

Contributions To Random Energy Models., Nabin Kumar Jana Dr.

Doctoral Theses

In this introductory chapter, we begin with a brief description of spin glasses in section 1. We are not physicists. The purpose of this section is to trace the history of the models. Section 2 gives a brief summary of the thesis and section 3 recalls certain known facts which will be used later in the thesis.Origin of the problem The models considered in this thesis have their origin in spin glass theory. Roughly, spin glass is a glassy state in a spin system or a disordered material exhibiting high magnetic frustration. The origin of this behavior can be either …


Theoretical Top Quark Cross Section At The Fermilab Tevatron And The Cern Lhc, Nikolaos Kidonakis, Ramona Vogt Oct 2008

Theoretical Top Quark Cross Section At The Fermilab Tevatron And The Cern Lhc, Nikolaos Kidonakis, Ramona Vogt

Faculty Articles

We present results for the top quark pair cross section at the Tevatron and the LHC. We use the resummed double differential cross section, employing the fully kinematics-dependent soft-anomalous-dimension matrices, to calculate the soft-gluon contributions at next-to-next-to-leading order (NNLO). We improve and update our previous estimates by refining our methods, including further subleading terms, and employing the most recent parton distribution function sets. The NNLO soft corrections significantly enhance the NLO cross section while considerably reducing the scale dependence. We provide a detailed discussion of all theoretical uncertainties in our calculation, including kinematics, scale, and parton distribution uncertainties, and clarify …


Physics Minor 09/15/2008, Curriculum Committee Sep 2008

Physics Minor 09/15/2008, Curriculum Committee

Curriculum Committee Reports

No abstract provided.


Physics B.A. Program And Curriculum Approval 09/12/2008, Curriculum Committee Sep 2008

Physics B.A. Program And Curriculum Approval 09/12/2008, Curriculum Committee

Curriculum Committee Reports

No abstract provided.


Community Detection In Complex Networks By Dynamical Simplex Evolution, Vladimir Gudkov, V. Montealegre, S. Nussinov, Z. Nussinov Jul 2008

Community Detection In Complex Networks By Dynamical Simplex Evolution, Vladimir Gudkov, V. Montealegre, S. Nussinov, Z. Nussinov

Faculty Publications

We benchmark the dynamical simplex evolution (DSE) method with several of the currently available algorithms to detect communities in complex networks by comparing correctly identified nodes for different levels of "fuzziness" of random networks composed of well-defined communities. The potential benefits of the DSE method to detect hierarchical substructures in complex networks are discussed.


Math In/And Physics [11th-12th Grade], Penny Whetstone Jul 2008

Math In/And Physics [11th-12th Grade], Penny Whetstone

Understanding by Design: Complete Collection

This unit is written to be taught during the first two weeks of the physics course. In any physics course, from conceptual physics up through graduate studies, there is a unique and significant dependence on the mathematical concepts and skills required to succeed in the course. A keen understanding of mathematics, as well as knowing how to apply the tools, is an important piece of the physics course. Math in/and Physics is designed to answer the question, “If this is a physics class, why do I have to do so much math?” The goals of this unit are designed to …


Soft And Collinear Enhancements To Top Quark And Higgs Cross Sections, Nikolaos Kidonakis Jul 2008

Soft And Collinear Enhancements To Top Quark And Higgs Cross Sections, Nikolaos Kidonakis

Faculty Articles

I present calculations of soft and collinear corrections to the cross-sections for single top quark production, and for Higgs production via bb H at the Tevatron and the LHC. I show that the corrections provide significant enhancements to the cross-sections in both cases. For single top production the soft gluon corrections dominate the cross-section, particularly in the s-channel and in tW production. For Higgs production it is shown that purely collinear terms have to be included as well to provide an accurate calculation.


Phys 2301 Course Proposal 04/23/08, Curriculum Committee Apr 2008

Phys 2301 Course Proposal 04/23/08, Curriculum Committee

Curriculum Committee Reports

No abstract provided.


Asymmetry Of Recoil Protons In Neutron Β Decay, Vladimir Gudkov Apr 2008

Asymmetry Of Recoil Protons In Neutron Β Decay, Vladimir Gudkov

Faculty Publications

A complete analysis of proton recoil asymmetry in neutron decay in the first order of radiative and recoil corrections is presented. The possible contributions from new physics are calculated in terms of low energy coupling constants, and the sensitivity of the measured asymmetry to models beyond the Standard Model are discussed.


The Equation, Spring 2008, College Of Science And Mathematics, Wright State University Apr 2008

The Equation, Spring 2008, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 4 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.


Physics Alumni Newsletter Spring 2008, Terry Goforth Mar 2008

Physics Alumni Newsletter Spring 2008, Terry Goforth

Physics Alumni Newsletter

Physics Alumni Newsletter

The Physics Alumni Newsletter is produced by the SWOSU Physics Department.

Our Engineering Physics students are recruited in fields such as electronics, aerospace, mechanical engineering, petroleum engineering and software engineering. Graduates also have careers in meteorology, architecture, education and more.


Limitations Of Decomposition-Based Imaging Of Longitudinal Absorber Configurations, S D. Campbell, S D. Grobe, I L. Goodin, Q Su, Rainer Grobe Feb 2008

Limitations Of Decomposition-Based Imaging Of Longitudinal Absorber Configurations, S D. Campbell, S D. Grobe, I L. Goodin, Q Su, Rainer Grobe

Faculty publications – Physics

We examine theoretically and experimentally an imaging scheme that uses the transverse intensity profile of the scattered light to reconstruct the locations of absorbers embedded in a turbid medium. This method is based on an a priori knowledge of the scattered light patterns associated with a single absorber that is located at various positions inside the medium. We discuss the range of validity of this method, and its sensitivity with regard to noise, and propose an algorithm to improve its accuracy.


A Geowall With Physics And Astronomy Applications, Phillip Dukes, Dan Bruton Jan 2008

A Geowall With Physics And Astronomy Applications, Phillip Dukes, Dan Bruton

Faculty Publications

A GeoWall is a passive stereoscopic projection system that can be used by students, teachers, and researchers for visualization of the structure and dynamics of three-dimensional systems and data. The type of system described here adequately provides 3-D visualization in natural color for large or small groups of viewers. The name “GeoWall” derives from its initial development to visualize data in the geosciences.1 An early GeoWall system was developed by Paul Morin at the electronic visualization laboratory at the University of Minnesota and was applied in an introductory geology course in spring of 2001. Since that time, several stereoscopic media, …


Ua1c7 Departmental Photos, Wku Archives Jan 2008

Ua1c7 Departmental Photos, Wku Archives

WKU Archives Collection Inventories

Images showing everyday activities of university departments.


The Problem Of Substantial Generation In Aristotle's Physical Writings, Michael Ivins Jan 2008

The Problem Of Substantial Generation In Aristotle's Physical Writings, Michael Ivins

Electronic Theses and Dissertations

This dissertation explores the relation between Aristotle's account of the generation of substances and his attempt to lay the foundations for his natural philosophy. The central question concerns the injunction posed by the Eleatic philosophers to the study of nature on the basis of the principle "ex nihilo nihil" which they formulated into argument against the intelligibility of nature. Aristotle's Physics begins with a sustained attempt to defeat the Eleatic prohibition by demonstrating that change in general can be understood once a few principles are established. My reading of the arguments that constitute Aristotle's refutation of the Eleatics and the …


Cross Sections And Beam Asymmetries For E ⃗ P → Enπ+ In The Nucleon Resonance Region For 1.7 ⩽ Q2 ⩽ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration Jan 2008

Cross Sections And Beam Asymmetries For E ⃗ P → Enπ+ In The Nucleon Resonance Region For 1.7 ⩽ Q2 ⩽ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

The exclusive electroproduction process e ⃗ p → e'nπ+ was measured in the range of the photon virtuality Q2 =1.7-4.5 GeV2, and the invariant mass range for the n π+ system of W=1.15-1.7 GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive π+ production from protons with nearly full coverage in the azimuthal and polar angles of the nπ+ center-of-mass system. The nπ+ channel has particular sensitivity to the isospin 1/2 excited nucleon states, and together with the pπ0 final state will serve …


A Single-Shot Measurement Of The Energy Of Product States In A Translation Invariant Spin Chain Can Replace Any Quantum Computation, Dominik Janzing, Pawel Wocjan, Shengyu Zhang Jan 2008

A Single-Shot Measurement Of The Energy Of Product States In A Translation Invariant Spin Chain Can Replace Any Quantum Computation, Dominik Janzing, Pawel Wocjan, Shengyu Zhang

Faculty Bibliography 2000s

In measurement-based quantum computation, quantum algorithms are implemented via sequences of measurements. We describe a translationally invariant finite-range interaction on a one-dimensional qudit chain and prove that a single-shot measurement of the energy of an appropriate computational basis state with respect to this Hamiltonian provides the output of any quantum circuit. The required measurement accuracy scales inverse polynomially with the size of the simulated quantum circuit. This shows that the implementation of energy measurements on generic qudit chains is as hard as the realization of quantum computation. Here, a 'measurement' is any procedure that samples from the spectral measurement induced …


Numerical And Adaptive Grid Methods For Ideal Magnetohydrodynamics, Burlen Loring Jan 2008

Numerical And Adaptive Grid Methods For Ideal Magnetohydrodynamics, Burlen Loring

Master's Theses and Capstones

In this thesis numerical finite difference methods for ideal magnetohydrodynamics (MHD) are investigated. A review of the relevant physics, essential for interpreting the results of numerical solutions and constructing validation cases, is presented. This review includes a discusion of the propagation of small amplitude waves in the MHD system as well as a thorough discussion of MHD shocks, contacts and rarefactions and how they can be pieced together to obtain a solutions to the MHD Riemann problem. Numerical issues relevant to the MHD system such as: the loss of nonlinear numerical stability in the presence of discontinuous solutions, the introduction …


First Results From Ideal 2-D Mhd Reconstruction: Magnetopause Reconnection Event Seen By Cluster, W. L. Teh, B. U. O. Sonnerup Jan 2008

First Results From Ideal 2-D Mhd Reconstruction: Magnetopause Reconnection Event Seen By Cluster, W. L. Teh, B. U. O. Sonnerup

Dartmouth Scholarship

We have applied a new reconstruction method (Sonnerup and Teh, 2008), based on the ideal single-fluid MHD equations in a steady-state, two-dimensional geometry, to a reconnection event observed by the Cluster-3 (C3) space- craft on 5 July 2001, 06:23 UT, at the dawn-side Northern- Hemisphere magnetopause. The event has been previously studied by use of Grad-Shafranov (GS) reconstruction, per- formed in the deHoffmann-Teller frame, and using the as- sumption that the flow effects were either negligible or the flow was aligned with the magnetic field. Our new method allows the reconstruction to be performed in the frame of reference moving …


Decomposition-Based Recovery Of Absorbers In Turbid Media, S D. Campbell, I L. Goodin, S D. Grobe, Qichang Su, Rainer Grobe Dec 2007

Decomposition-Based Recovery Of Absorbers In Turbid Media, S D. Campbell, I L. Goodin, S D. Grobe, Qichang Su, Rainer Grobe

Faculty publications – Physics

We suggest that the concept of the point-spread function traditionally used to predict the blurred image pattern of various light sources embedded inside turbid media can be generalized under certain conditions to predict also the presence and location of spatially localized absorbing inhomogeneities based on shadow point-spread functions associated with each localized absorber in the medium. The combined image obtained from several absorbers can then be decomposed approximately into the arithmetic sums of these individual shadow point-spread functions with suitable weights that can be obtained from multiple-regression analysis. This technique permits the reconstruction of the location of absorbers.