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Articles 1501 - 1530 of 6056

Full-Text Articles in Physical Sciences and Mathematics

Nonresonant Two-Photon Transitions In Length And Velocity Gauges, Ulrich D. Jentschura Aug 2016

Nonresonant Two-Photon Transitions In Length And Velocity Gauges, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We reexamine the invariance of two-photon transition matrix elements and corresponding two-photon Rabi frequencies under the "gauge" transformation from the length to the velocity gauge. It is shown that gauge invariance, in the most general sense, only holds at exact resonance, for both one-color as well as two-color absorption. The arguments leading to this conclusion are supported by analytic calculations which express the matrix elements in terms of hypergeometric functions, and ramified by a "master identity" which is fulfilled by off-diagonal matrix elements of the Schrödinger propagator under the transformation from the velocity to the length gauge. The study of …

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Bic-Lsu: Big Data Research Integration With Cyberinfrastructure For Lsu, Chui Hui Chiu, Nathan Lewis, Dipak Kumar Singh, Arghya Kusum Das, Mohammad M. Jalazai, Richard Platania, Sayan Goswami, Kisung Lee, Seung Jong Park Jul 2016

Bic-Lsu: Big Data Research Integration With Cyberinfrastructure For Lsu, Chui Hui Chiu, Nathan Lewis, Dipak Kumar Singh, Arghya Kusum Das, Mohammad M. Jalazai, Richard Platania, Sayan Goswami, Kisung Lee, Seung Jong Park

Computer Science Faculty Research & Creative Works

In recent years, big data analysis has been widely applied to many research fields including biology, physics, transportation, and material science. Even though the demands for big data migration and big data analysis are dramatically increasing in campus IT infrastructures, there are several technical challenges that need to be addressed. First of all, frequent big data transmission between storage systems in different research groups imposes heavy burdens on a regular campus network. Second, the current campus IT infrastructure is not designed to fully utilize the hardware capacity for big data migration and analysis. Last but not the least, running big …

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Ferromagnetic Quantum Critical Point Avoided By The Appearance Of Another Magnetic Phase In Lacrge₃ Under Pressure, Valentin Taufour, Udhara S. Kaluarachchi, Rustem Khasanov, Manh Cuong Nguyen, Zurab Guguchia, Pabitra Kumar Biswas, Pietro Bonfà, Roberto De Renzi, Xiao Lin, For Full List Of Authors, See Publisher's Website. Jul 2016

Ferromagnetic Quantum Critical Point Avoided By The Appearance Of Another Magnetic Phase In Lacrge₃ Under Pressure, Valentin Taufour, Udhara S. Kaluarachchi, Rustem Khasanov, Manh Cuong Nguyen, Zurab Guguchia, Pabitra Kumar Biswas, Pietro Bonfà, Roberto De Renzi, Xiao Lin, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The temperature-pressure phase diagram of the ferromagnet LaCrGe3 is determined for the first time from a combination of magnetization, muon-spin-rotation, and electrical resistivity measurements. The ferromagnetic phase is suppressed near 2.1 GPa, but quantum criticality is avoided by the appearance of a magnetic phase, likely modulated, AFMQ. Our density functional theory total energy calculations suggest a near degeneracy of antiferromagnetic states with small magnetic wave vectors Q allowing for the potential of an ordering wave vector evolving from Q = 0 to finite Q, as expected from the most recent theories on ferromagnetic quantum criticality. Our findings …

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Multiple Fermi Surfaces In Superconducting Nb-Doped Bi₂Se₃, B. J. Lawson, Paul Corbae, Gang Li, Fan Yu, Tomoya Asaba, Colin Tinsman, Y. Qiu, Julia E. Medvedeva, Yew San Hor, L. Li Jul 2016

Multiple Fermi Surfaces In Superconducting Nb-Doped Bi₂Se₃, B. J. Lawson, Paul Corbae, Gang Li, Fan Yu, Tomoya Asaba, Colin Tinsman, Y. Qiu, Julia E. Medvedeva, Yew San Hor, L. Li

Physics Faculty Research & Creative Works

Topological insulator Bi2Se3 has shown a number of interesting physical properties. Doping Bi2Se3 with copper or strontium has been demonstrated to make the material superconducting and potentially even a topological superconductor. The recent discovery of superconducting niobium-doped Bi2Se3 reveals an exciting new physical phenomenon, the coexistence of superconductivity and magnetic ordering, as well as signatures of an odd-parity p-wave superconducting order. To understand this new phenomenon, a detailed knowledge of the electronic structure is needed. We present an observation of quantum oscillations in the magnetization (the de Haas-van Alphen effect) of …

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Supplement: "Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914" (2016, Apjl, 826, L13), Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jul 2016

Supplement: "Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914" (2016, Apjl, 826, L13), Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands.

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The First Potential Energy Surfaces For The C₆Hˉ-H₂ And C₆Hˉ-He Collisional Systems And Their Corresponding Inelastic Cross Sections, Kyle M. Walker, Fabien Dumouchel, François Lique, Richard Dawes Jul 2016

The First Potential Energy Surfaces For The C₆Hˉ-H₂ And C₆Hˉ-He Collisional Systems And Their Corresponding Inelastic Cross Sections, Kyle M. Walker, Fabien Dumouchel, François Lique, Richard Dawes

Chemistry Faculty Research & Creative Works

Molecular anions have recently been detected in the interstellar and circumstellar media. Accurate modeling of their abundance requires calculations of collisional data with the most abundant species that are usually He atoms and H2 molecules. In this paper, we focus on the collisional excitation of the first observed molecular anion, C6H-, by He and H2. Theoretical calculations of collisional cross sections rely generally on ab initio interaction potential energy surfaces (PESs). Hence, we present here the first PESs for the C6H--H2 and C6H--He van …

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Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jul 2016

Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the …

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Doping Evolution Of The Superconducting Gap Structure In The Underdoped Iron Arsenide Ba₁₋ₓkₓfe₂As₂ Revealed By Thermal Conductivity, J. Ph Reid, M. A. Tanatar, X. G. Luo, H. Shakeripour, S. René De Cotret, A. Juneau-Fecteau, J. Chang, B. Shen, H. H. Wen, Hyunsoo Kim, For Full List Of Authors, See Publisher's Website. Jun 2016

Doping Evolution Of The Superconducting Gap Structure In The Underdoped Iron Arsenide Ba₁₋ₓkₓfe₂As₂ Revealed By Thermal Conductivity, J. Ph Reid, M. A. Tanatar, X. G. Luo, H. Shakeripour, S. René De Cotret, A. Juneau-Fecteau, J. Chang, B. Shen, H. H. Wen, Hyunsoo Kim, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The thermal conductivity κ of the iron-arsenide superconductor Ba1-xKxFe2As2 was measured for heat currents parallel and perpendicular to the tetragonal c axis at temperatures down to 50 mK and in magnetic fields up to 15 T. Measurements were performed on samples with compositions ranging from optimal doping (x = 0.34, Tc = 39 K) down to dopings deep into the region where antiferromagnetic order coexists with superconductivity (x = 0.16, Tc = 7 K). In zero field, there is no residual linear term in κ(T) as T→0 at any doping, whether …

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Sorting Under Forbidden Comparisons, Avah Banerjee, Dana Richards Jun 2016

Sorting Under Forbidden Comparisons, Avah Banerjee, Dana Richards

Computer Science Faculty Research & Creative Works

In this paper we study the problem of sorting under forbidden comparisons where some pairs of elements may not be compared (forbidden pairs). Along with the set of elements V the input to our problem is a graph G(V, E), whose edges represents the pairs that we can compare in constant time. Given a graph with n vertices and m =(n2) - q edges we propose the first non-trivial deterministic algorithm which makes O((q + n) log n) comparisons with a total complexity of O(n2 + qω/2), where ω is the …

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Chaotic Advection-Driven Mixing In Unsteady Three-Dimensional Mhd Flows In Microfluidic Devices, Fangping Yuan, Kakkattukuzhy M. Isaac Jun 2016

Chaotic Advection-Driven Mixing In Unsteady Three-Dimensional Mhd Flows In Microfluidic Devices, Fangping Yuan, Kakkattukuzhy M. Isaac

Collaborative Research: Actively Controllable Microfluidics with Film-Confined Redox-Magnetohydrodynamics -- Video and Data

No abstract provided.

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Comparison Of Experimental And Theoretical Triple Differential Cross Sections For The Single Ionization Of Co₂ (1Πg) By Electron Impact, Zehra N. Ozer, Esam Ali, Mevlut Dogan, Murat Yavuz, Osman Alwan, Adnan Naja, Ochbadrakh Chuluunbaatar, Boghos B. Joulakian, Chuan-Gang Ning, James Colgan, Don H. Madison Jun 2016

Comparison Of Experimental And Theoretical Triple Differential Cross Sections For The Single Ionization Of Co₂ (1Πg) By Electron Impact, Zehra N. Ozer, Esam Ali, Mevlut Dogan, Murat Yavuz, Osman Alwan, Adnan Naja, Ochbadrakh Chuluunbaatar, Boghos B. Joulakian, Chuan-Gang Ning, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

Experimental and theoretical triple differential cross sections for intermediate-energy (250 eV) electron-impact single ionization of the CO2 are presented for three fixed projectile scattering angles. Results are presented for ionization of the outermost 1πg molecular orbital of CO2 in a coplanar asymmetric geometry. The experimental data are compared to predictions from the three-center Coulomb continuum approximation for triatomic targets, and the molecular three-body distorted wave (M3DW) model. It is observed that while both theories are in reasonable qualitative agreement with experiment, the M3DW is in the best overall agreement with experiment.

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Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Argon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Alexander Dorn, Don H. Madison, Klaus Bartschat Jun 2016

Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Argon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Alexander Dorn, Don H. Madison, Klaus Bartschat

Physics Faculty Research & Creative Works

As a further test of advanced theoretical methods to describe electron-impact single-ionization processes in complex atomic targets, we extended our recent work on Ne(2p) ionization [X. Ren, S. Amami, O. Zatsarinny, T. Pflüger, M. Weyland, W. Y. Baek, H. Rabus, K. Bartschat, D. Madison, and A. Dorn, Phys. Rev. A 91, 032707 (2015)PLRAAN1050-294710.1103/PhysRevA.91.032707] to Ar(3p) ionization at the relatively low incident energy of E0 = 66 eV. The experimental data were obtained with a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission. We present experimental data for detection angles of 10, …

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Influence Of Orbital Symmetry On Diffraction Imaging With Rescattering Electron Wave Packets, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michele Sclafani, Hugo Pires, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, Thomas Pfeifer, C. D. Lin, Jens Biegert Jun 2016

Influence Of Orbital Symmetry On Diffraction Imaging With Rescattering Electron Wave Packets, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michele Sclafani, Hugo Pires, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, Thomas Pfeifer, C. D. Lin, Jens Biegert

Physics Faculty Research & Creative Works

The ability to directly follow and time-resolve the rearrangement of the nuclei within molecules is a frontier of science that requires atomic spatial and few-femtosecond temporal resolutions. While laser-induced electron diffraction can meet these requirements, it was recently concluded that molecules with particular orbital symmetries (such as πg) cannot be imaged using purely backscattering electron wave packets without molecular alignment. Here, we demonstrate, in direct contradiction to these findings, that the orientation and shape of molecular orbitals presents no impediment for retrieving molecular structure with adequate sampling of the momentum transfer space. We overcome previous issues by showcasing …

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Gw150914: First Results From The Search For Binary Black Hole Coalescence With Advanced Ligo, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jun 2016

Gw150914: First Results From The Search For Binary Black Hole Coalescence With Advanced Ligo, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On September 14, 2015, at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) simultaneously observed the binary black hole merger GW150914. We report the results of a matched-filter search using relativistic models of compact-object binaries that recovered GW150914 as the most significant event during the coincident observations between the two LIGO detectors from September 12 to October 20, 2015 GW150914 was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203000 years, equivalent to a significance greater than 5.1 σ.

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Shear Wave Splitting Analyses In Tian Shan: Geodynamic Implications Of Complex Seismic Anisotropy, Solomon G. Cherie, Stephen S. Gao, Kelly H. Liu, Ahmed A. Elsheikh, Fansheng Kong, Cory A. Reed, Bin B. Yang Jun 2016

Shear Wave Splitting Analyses In Tian Shan: Geodynamic Implications Of Complex Seismic Anisotropy, Solomon G. Cherie, Stephen S. Gao, Kelly H. Liu, Ahmed A. Elsheikh, Fansheng Kong, Cory A. Reed, Bin B. Yang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Tian Shan is a tectonically complex intracontinental orogenic belt situated between the Tarim Basin and the Kazakh Shield. The vast majority of the previous shear wave splitting (SWS) measurements were presented as station averages, which are only valid when the anisotropy structure can be approximated by a single layer of anisotropy with a horizontal axis of symmetry, i.e., a model of simple anisotropy. A variety of anisotropy-forming hypotheses have been proposed based on the station-averaged measurements. In this study, we measure the splitting parameters at 25 stations that recorded high-quality data from a wide back azimuthal range for the …

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Big Data Management And Analytics For Mobile Crowd Sensing, Tingting Chen, Fan Wu, Tony Tie Luo, Mea Wang, Qirong Ho Jun 2016

Big Data Management And Analytics For Mobile Crowd Sensing, Tingting Chen, Fan Wu, Tony Tie Luo, Mea Wang, Qirong Ho

Computer Science Faculty Research & Creative Works

No abstract provided.

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Gw151226: Observation Of Gravitational Waves From A 22-Solar-Mass Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jun 2016

Gw151226: Observation Of Gravitational Waves From A 22-Solar-Mass Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, …

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Properties Of The Binary Black Hole Merger Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jun 2016

Properties Of The Binary Black Hole Merger Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 36-4+5 M⊙ and 29-4+4M⊙; for each parameter we report the median value and the range of the 90% credible interval. …

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The C-H Stretching Features At 3.2-3.5 Μm Of Polycyclic Aromatic Hydrocarbons With Aliphatic Sidegroups, Xuejuan Yang, Aigen Li, Rainer Glaser, Jianxin Zhong Jun 2016

The C-H Stretching Features At 3.2-3.5 Μm Of Polycyclic Aromatic Hydrocarbons With Aliphatic Sidegroups, Xuejuan Yang, Aigen Li, Rainer Glaser, Jianxin Zhong

Chemistry Faculty Research & Creative Works

The so-called "unidentified" infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are ubiquitously seen in a wide variety of astrophysical regions. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, e.g., polycyclic aromatic hydrocarbon (PAH) molecules. The 3.3 μm aromatic C-H stretching feature is often accompanied by a weaker feature at 3.4 μm. The latter is generally thought to result from the C-H stretch of aliphatic groups attached to the aromatic systems. The ratio of the observed intensity of the 3.3 μm aromatic C-H feature to that of the 3.4 …

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A New Set Of Potential Energy Surfaces For Hco: Influence Of Renner-Teller Coupling On The Bound And Resonance Vibrational States, Steve Alexandre Ndengué, Richard Dawes, Hua Guo Jun 2016

A New Set Of Potential Energy Surfaces For Hco: Influence Of Renner-Teller Coupling On The Bound And Resonance Vibrational States, Steve Alexandre Ndengué, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

It is commonly understood that the Renner-Teller effect can strongly influence the spectroscopy of molecules through coupling of electronic states. Here we investigate the vibrational bound states and low-lying resonances of the formyl radical treating the Renner-Teller coupled X2A' and Ã2A" states using the MultiConfiguration Time Dependent Hartree (MCTDH) method. The calculations were performed using the improved relaxation method for the bound states and a recently published extension to compute resonances. A new set of accurate global potential energy surfaces were computed at the explicitly correlated multireference configuration interaction (MRCI-F12) level and yielded remarkably close agreement with experiment in this …

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Search For Transient Gravitational Waves In Coincidence With Short-Duration Radio Transients During 2007-2013, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jun 2016

Search For Transient Gravitational Waves In Coincidence With Short-Duration Radio Transients During 2007-2013, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present an archival search for transient gravitational-wave bursts in coincidence with 27 single-pulse triggers from Green Bank Telescope pulsar surveys, using the LIGO, Virgo, and GEO interferometer network. We also discuss a check for gravitational-wave signals in coincidence with Parkes fast radio bursts using similar methods. Data analyzed in these searches were collected between 2007 and 2013. Possible sources of emission of both short-duration radio signals and transient gravitational-wave emission include starquakes on neutron stars, binary coalescence of neutron stars, and cosmic string cusps. While no evidence for gravitational-wave emission in coincidence with these radio transients was found, the …

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Probing And Extracting The Structure Of Vibrating Sf₆ Molecules With Inner-Shell Photoelectrons, Ngoc-Ty Nguyen, R. R. Lucchese, C. D. Lin, Anh-Thu Le Jun 2016

Probing And Extracting The Structure Of Vibrating Sf₆ Molecules With Inner-Shell Photoelectrons, Ngoc-Ty Nguyen, R. R. Lucchese, C. D. Lin, Anh-Thu Le

Physics Faculty Research & Creative Works

We propose a scheme for probing the structure of vibrating molecules with photoelectrons generated from ultrashort soft-x-ray pulses. As an example we analyze below-100-eV photoelectrons liberated from the S(2p) orbital of vibrating SF₆ molecules to image very small structural changes of molecular vibration. In particular, photoionization cross sections and photoelectron angular distributions (PAD) at nonequilibrium geometries can be retrieved accurately with photoelectrons near the shape resonance at 13 eV. This is achieved with a pump-probe scheme, in which the symmetric stretch mode is first Raman excited predominantly by a relatively short laser pulse and then later probed at different time …

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Reply To "Comment On 'Classical Description Of H(1s) And H* (N=2) For Cross-Section Calculations Relevant To Charge-Exchange Diagnostics'", N. D. Cariatore, Sebastian Otranto, Ronald E. Olson Jun 2016

Reply To "Comment On 'Classical Description Of H(1s) And H* (N=2) For Cross-Section Calculations Relevant To Charge-Exchange Diagnostics'", N. D. Cariatore, Sebastian Otranto, Ronald E. Olson

Physics Faculty Research & Creative Works

In reply to the Comment of Jorge et al. [Phys. Rev. A 93, 066701 (2016)], we agree and reconfirm that the alternative classical trajectory Monte Carlo method (called hydrogenic-Z-CTMC) radial distributions for H*(n = 2) we recently published are not stable in time. However, we show that such lack of stability which is more noticeable for H(2s) than for H(2p) is due to the initialization procedure employed and not to the hydrogenic-Z-CTMC method itself. A new set of completely stable hydrogenic-Z-CTMC calculations for H*(n = 2) is introduced and found in very good agreement with standard microcanonical results reinforcing our …

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Experimental And Theoretical Triple-Differential Cross Sections For Tetrahydrofuran Ionized By Low-Energy 26-Ev-Electron Impact, Esam Ali, Xueguang Ren, Alexander Dorn, Chuangang Ning, James Colgan, Don H. Madison Jun 2016

Experimental And Theoretical Triple-Differential Cross Sections For Tetrahydrofuran Ionized By Low-Energy 26-Ev-Electron Impact, Esam Ali, Xueguang Ren, Alexander Dorn, Chuangang Ning, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We report an experimental and theoretical study of low-energy electron-impact ionization of tetrahydrofuran, which is a molecule of biological interest. The experiments were performed using an advanced reaction microscope specially built for electron-impact ionization studies. The theoretical calculations were performed within the molecular three-body distorted-wave model. Reasonably good agreement is found between experiment and theory.

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High-Energy Neutrino Follow-Up Search Of Gravitational Wave Event Gw150914 With Antares And Icecube, S. Adrian-Martinez, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jun 2016

High-Energy Neutrino Follow-Up Search Of Gravitational Wave Event Gw150914 With Antares And Icecube, S. Adrian-Martinez, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present the high-energy-neutrino follow-up observations of the first gravitational wave transient GW150914 observed by the Advanced LIGO detectors on September 14, 2015. We search for coincident neutrino candidates within the data recorded by the IceCube and Antares neutrino detectors. A possible joint detection could be used in targeted electromagnetic follow-up observations, given the significantly better angular resolution of neutrino events compared to gravitational waves. We find no neutrino candidates in both temporal and spatial coincidence with the gravitational wave event. Within ±500 s of the gravitational wave event, the number of neutrino candidates detected by IceCube and Antares were …

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New-Sum: A Novel Online Abft Scheme For General Iterative Methods, Dingwen Tao, Shuaiwen Leon Song, Sriram Krishnamoorthy, Panruo Wu, Xin Liang, Eddy Z. Zhang, For Full List Of Authors, See Publisher's Website. May 2016

New-Sum: A Novel Online Abft Scheme For General Iterative Methods, Dingwen Tao, Shuaiwen Leon Song, Sriram Krishnamoorthy, Panruo Wu, Xin Liang, Eddy Z. Zhang, For Full List Of Authors, See Publisher's Website.

Computer Science Faculty Research & Creative Works

Emerging high-performance computing platforms, with large component counts and lower power margins, are anticipated to be more susceptible to soft errors in both logic circuits and memory subsystems. We present an online algorithm-based fault tolerance (ABFT) approach to efficiently detect and recover soft errors for general iterative methods. We design a novel checksum-based encoding scheme for matrix-vector multiplication that is resilient to both arithmetic and memory errors. Our design decouples the checksum updating process from the actual computation, and allows adaptive checksum overhead control. Building on this new encoding mechanism, we propose two online ABFT designs that can effectively recover …

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Towards Practical Algorithm Based Fault Tolerance In Dense Linear Algebra, Panruo Wu, Qiang Guan, Nathan Debardeleben, Sean Blanchard, Dingwen Tao, Xin Liang, For Full List Of Authors, See Publisher's Website. May 2016

Towards Practical Algorithm Based Fault Tolerance In Dense Linear Algebra, Panruo Wu, Qiang Guan, Nathan Debardeleben, Sean Blanchard, Dingwen Tao, Xin Liang, For Full List Of Authors, See Publisher's Website.

Computer Science Faculty Research & Creative Works

Algorithm based fault tolerance (ABFT) attracts renewed interest for its extremely low overhead and good scalability. However the fault model used to design ABFT has been either abstract, simplistic, or both, leaving a gap between what occurs at the architecture level and what the algorithm expects. As the fault model is the deciding factor in choosing an effective checksum scheme, the resulting ABFT techniques have seen limited impact in practice. In this paper we seek to close the gap by directly using a comprehensive architectural fault model and devise a comprehensive ABFT scheme that can tolerate multiple architectural faults of …

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Lepton Pair Čerenkov Radiation Emitted By Tachyonic Neutrinos: Lorentz-Covariant Approach And Icecube Data, Ulrich D. Jentschura, Robert B. Ehrlich May 2016

Lepton Pair Čerenkov Radiation Emitted By Tachyonic Neutrinos: Lorentz-Covariant Approach And Icecube Data, Ulrich D. Jentschura, Robert B. Ehrlich

Physics Faculty Research & Creative Works

Current experiments do not exclude the possibility that one or more neutrinos are very slightly superluminal or that they have a very small tachyonic mass. Important bounds on the size of a hypothetical tachyonic neutrino mass term are set by lepton pair Čerenkov radiation (LPCR), that is, by the decay channel → e+ e- , which proceeds via a virtual Z0 boson. Here, we use a Lorentz-invariant dispersion relation which leads to very tight constraints on the tachyonic mass of neutrinos; we also calculate decay and energy loss rates. A possible cutoff seen in the IceCube neutrino …

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Dynamical Mechanisms Leading To Equilibration In Two-Component Gases, Stephan De Bievre, Carlos Mejia-Monasterio, Paul Ernest Parris May 2016

Dynamical Mechanisms Leading To Equilibration In Two-Component Gases, Stephan De Bievre, Carlos Mejia-Monasterio, Paul Ernest Parris

Physics Faculty Research & Creative Works

Demonstrating how microscopic dynamics cause large systems to approach thermal equilibrium remains an elusive, longstanding, and actively pursued goal of statistical mechanics. We identify here a dynamical mechanism for thermalization in a general class of two-component dynamical Lorentz gases and prove that each component, even when maintained in a nonequilibrium state itself, can drive the other to a thermal state with a well-defined effective temperature.

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Tests Of General Relativity With Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. May 2016

Tests Of General Relativity With Gw150914, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following …

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