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- Gravitational waves (5)
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Articles 1 - 30 of 115
Full-Text Articles in Physical Sciences and Mathematics
Clustering Of Sloan Digital Sky Survey Iii Photometric Luminous Galaxies: The Measurement, Systematics, And Cosmological Implications, Shirley Ho, Antonio J. Cuesta, Hee-Jong Seo, Roland De Putter, Ashley J. Ross, Martin White, Nikhil Padmanabhan, Shun Saito, For Full List Of Authors, See Publisher's Website.
Clustering Of Sloan Digital Sky Survey Iii Photometric Luminous Galaxies: The Measurement, Systematics, And Cosmological Implications, Shirley Ho, Antonio J. Cuesta, Hee-Jong Seo, Roland De Putter, Ashley J. Ross, Martin White, Nikhil Padmanabhan, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg2, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg2 and probes a volume of 3 h-3 Gpc3, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. …
Acoustic Scale From The Angular Power Spectra Of Sdss-Iii Dr8 Photometric Luminous Galaxies, Hee-Jong Seo, Shirley Ho, Martin White, Antonio J. Cuesta, Ashley J. Ross, Shun Saito, For Full List Of Authors, See Publisher's Website.
Acoustic Scale From The Angular Power Spectra Of Sdss-Iii Dr8 Photometric Luminous Galaxies, Hee-Jong Seo, Shirley Ho, Martin White, Antonio J. Cuesta, Ashley J. Ross, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We measure the acoustic scale from the angular power spectra of the Sloan Digital Sky Survey III (SDSS-III) Data Release 8 imaging catalog that includes 872, 921 galaxies over ~10,000 deg2 between 0.45 < z < 0.65. The extensive spectroscopic training set of the Baryon Oscillation Spectroscopic Survey luminous galaxies allows precise estimates of the true redshift distributions of galaxies in our imaging catalog. Utilizing the redshift distribution information, we build templates and fit to the power spectra of the data, which are measured in our companion paper, to derive the location of Baryon acoustic oscillations (BAOs) while marginalizing over many free parameters to exclude nearly all of the non-BAO signal. We derive the ratio of the angular diameter distance to the sound horizon scale DA(z)/rs = 9.212+0.416-0.404 at z = 0.54, and therefore DA (z) = 1411 ± 65 Mpc at z = 0.54; the result is fairly independent of assumptions on the underlying cosmology. Our measurement of angular diameter distance DA(z) is 1.4σ higher than what is expected for the concordance ΛCDM, in accordance to the trend of other spectroscopic BAO measurements for …
Laser-Induced Electron Diffraction For Probing Rare Gas Atoms, Junliang Xu, Cosmin I. Blaga, Anthony D. Dichiara, Emily Sistrunk, Kaikai Zhang, Zhangjin Chen, Anh-Thu Le, Toru Morishita, C. D. Lin, Pierre Agostini, Louis F. Dimauro
Laser-Induced Electron Diffraction For Probing Rare Gas Atoms, Junliang Xu, Cosmin I. Blaga, Anthony D. Dichiara, Emily Sistrunk, Kaikai Zhang, Zhangjin Chen, Anh-Thu Le, Toru Morishita, C. D. Lin, Pierre Agostini, Louis F. Dimauro
Physics Faculty Research & Creative Works
Recently, using midinfrared laser-induced electron diffraction (LIED), snapshots of a vibrating diatomic molecule on a femtosecond time scale have been captured [C.I. Blaga et al., Nature (London) 483, 194 (2012)]. In this Letter, a comprehensive treatment for the atomic LIED response is reported, a critical step in generalizing this imaging method. Electron-ion differential cross sections (DCSs) of rare gas atoms are extracted from measured angular-resolved, high-energy electron momentum distributions generated by intense midinfrared lasers. Following strong-field ionization, the high-energy electrons result from elastic rescattering of a field-driven wave packet with the parent ion. For recollision energies [greater or equal] 100eV, …
Rounding Of A First-Order Quantum Phase Transition To A Strong-Coupling Critical Point, Fawaz Hrahsheh, Jose A. Hoyos, Thomas Vojta
Rounding Of A First-Order Quantum Phase Transition To A Strong-Coupling Critical Point, Fawaz Hrahsheh, Jose A. Hoyos, Thomas Vojta
Physics Faculty Research & Creative Works
We investigate the effects of quenched disorder on first-order quantum phase transitions on the example of the N-color quantum Ashkin-Teller model. By means of a strong-disorder renormalization group, we demonstrate that quenched disorder rounds the first-order quantum phase transition to a continuous one for both weak and strong coupling between the colors. In the strong-coupling case, we find a distinct type of infinite-randomness critical point characterized by additional internal degrees of freedom. We investigate its critical properties in detail and find stronger thermodynamic singularities than in the random transverse field Ising chain. We also discuss the implications for higher spatial …
An Evaluation Of Fairness Among Heterogeneous Tcp Variants Over 10gbps High-Speed Networks, Lin Xue, Suman Kumary, Cheng Cui, Seung Jong Park
An Evaluation Of Fairness Among Heterogeneous Tcp Variants Over 10gbps High-Speed Networks, Lin Xue, Suman Kumary, Cheng Cui, Seung Jong Park
Computer Science Faculty Research & Creative Works
Several high-speed TCP variants are adopted by end users and therefore, heterogeneous congestion control has become the characteristic of newly emerging high-speed networks. In contrast to homogeneous TCP flows, fairness among heterogeneous TCP flows now depends on router parameters such as queue management scheme, buffer size, etc. To the best of our knowledge, this is the first evaluation of fairness among heterogeneous TCP variants over 10Gbps high-speed networks. Our evaluation scenarios for heterogeneous TCP flows consist of TCP variants with substantial presence in current Internet; therefore, TCP-SACK, CUBIC and HSTCP compete for bottleneck bandwidth. Experimental results for fairness are presented …
Disordered Bosons In One Dimension: From Weak- To Strong-Randomness Criticality, Fawaz Hrahsheh, Thomas Vojta
Disordered Bosons In One Dimension: From Weak- To Strong-Randomness Criticality, Fawaz Hrahsheh, Thomas Vojta
Physics Faculty Research & Creative Works
We investigate the superfluid-insulator quantum phase transition of one-dimensional bosons with off-diagonal disorder by means of large-scale Monte Carlo simulations. For weak disorder, we find the transition to be in the same universality class as the superfluid-Mott insulator transition of the clean system. The nature of the transition changes for stronger disorder. Beyond a critical disorder strength, we find nonuniversal, disorder-dependent critical behavior. We compare our results to recent perturbative and strong-disorder renormalization group predictions. We also discuss experimental implications as well as extensions of our results to other systems.
Quantum Dynamics In Atomic-Fountain Experiments For Measuring The Electric Dipole Moment Of The Electron With Improved Sensitivity, Benedikt J. Wundt, Charles T. Munger, Ulrich D. Jentschura
Quantum Dynamics In Atomic-Fountain Experiments For Measuring The Electric Dipole Moment Of The Electron With Improved Sensitivity, Benedikt J. Wundt, Charles T. Munger, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
An improved measurement of the electron electric dipole moment (EDM) appears feasible using groundstate alkali atoms in an atomic fountain in which a strong electric field, which couples to a conceivable EDM, is applied perpendicular to the fountain axis. In a practical fountain, the ratio of the atomic tensor Stark shift to the Zeeman shift is a factor μ ~ 100.We expand the complete time-evolution operator in inverse powers of this ratio; complete results are presented for atoms of total spin F = 3, 4, and 5. For a specific set of entangled hyperfine sublevels (coherent states), potential systematic errors …
Monte Carlo Simulations Of The Clean And Disordered Contact Process In Three Dimensions, Thomas Vojta
Monte Carlo Simulations Of The Clean And Disordered Contact Process In Three Dimensions, Thomas Vojta
Physics Faculty Research & Creative Works
The absorbing-state transition in the three-dimensional contact process with and without quenched randomness is investigated by means of Monte Carlo simulations. In the clean case, a reweighting technique is combined with a careful extrapolation of the data to infinite time to determine with high accuracy the critical behavior in the three-dimensional directed percolation universality class. In the presence of quenched spatial disorder, our data demonstrate that the absorbing-state transition is governed by an unconventional infinite-randomness critical point featuring activated dynamical scaling. The critical behavior of this transition does not depend on the disorder strength, i.e., it is universal. Close to …
Injecting Large Volumes Of Preformed Particle Gel For Water Conformance Control, Baojun Bai, Mingzhen Wei, Yuzhang Liu
Injecting Large Volumes Of Preformed Particle Gel For Water Conformance Control, Baojun Bai, Mingzhen Wei, Yuzhang Liu
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
This paper describes Preformed Particle Gel (PPG) treatments for in-depth fluid diversion in four injection wells located in the northern section of the Lamadian reservoir, Daqing oilfield, China, which is a sandstone reservoir with thick heterogeneous pay zones. Forty-six producers were connected to the four treated injectors with an average water cut of 95.4% before PPG treatments. A large volume (more than 1 000 m3) of PPG suspension with concentrations of 1 900-2 500 mg/L and particle sizes of 0.06-3.0 mm was injected into each well, each injection spanning approximately four months. The injection PPG suspension volumes range …
Theory Of High Harmonic Generation For Probing Time-Resolved Large-Amplitude Molecular Vibrations With Ultrashort Intense Lasers, Anh-Thu Le, Toru Morishita, R. R. Lucchese, C. D. Lin
Theory Of High Harmonic Generation For Probing Time-Resolved Large-Amplitude Molecular Vibrations With Ultrashort Intense Lasers, Anh-Thu Le, Toru Morishita, R. R. Lucchese, C. D. Lin
Physics Faculty Research & Creative Works
We present a theory that incorporates the vibrational degrees of freedom in a high-order harmonic generation (HHG) process with ultrashort intense laser pulses. In this model, laser-induced time-dependent transition dipoles for each fixed molecular geometry are added coherently, weighted by the laser-driven time-dependent nuclear wave packet distribution. We show that the nuclear distribution can be strongly modified by the HHG driving laser. The validity of this model is first checked against results from the numerical solution of the time-dependent Schrödinger equation for a simple model system. We show that in combination with the established quantitative rescattering theory this model is …
Swift Follow-Up Observations Of Candidate Gravitational-Wave Transient Events, P. A. Evans, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Swift Follow-Up Observations Of Candidate Gravitational-Wave Transient Events, P. A. Evans, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors (within less than 10 minutes) and their candidate sky locations were observed by the Swift observatory (within 12 hr). Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them …
Network-Aware Scheduling Of Mapreduce Framework On Distributed Clusters Over High Speed Networks, Praveenkumar Kondikoppa, Chui Hui Chiu, Cheng Cui, Lin Xue, Seung Jong Park
Network-Aware Scheduling Of Mapreduce Framework On Distributed Clusters Over High Speed Networks, Praveenkumar Kondikoppa, Chui Hui Chiu, Cheng Cui, Lin Xue, Seung Jong Park
Computer Science Faculty Research & Creative Works
Google's MapReduce has gained significant popularity as a platform for large scale distributed data processing. Hadoop [1] is an open-source implementation of MapReduce [11] framework, originally it was developed to operate over single cluster environment and could not be leveraged for distributed data processing across federated clusters. At multiple federated clusters connected with high-speed networks, computing resources are provisioned from any of the clusters from the federation. Placement of map tasks close to its data split is critical for performance of Hadoop. In this work, we add network awareness in Hadoop while scheduling the map tasks over federated clusters. We …
Random Fields At A Nonequilibrium Phase Transition, Hatem Barghathi, Thomas Vojta
Random Fields At A Nonequilibrium Phase Transition, Hatem Barghathi, Thomas Vojta
Physics Faculty Research & Creative Works
We study nonequilibrium phase transitions in the presence of disorder that locally breaks the symmetry between two equivalent macroscopic states. In low-dimensional equilibrium systems, such random-field disorder is known to have dramatic effects: it prevents spontaneous symmetry breaking and completely destroys the phase transition. In contrast, we show that the phase transition of the one-dimensional generalized contact process persists in the presence of random-field disorder. The ultraslow dynamics in the symmetry-broken phase is described by a Sinai walk of the domain walls between two different absorbing states. We discuss the generality and limitations of our theory, and we illustrate our …
Search For Gravitational Waves Associated With Gamma-Ray Bursts During Ligo Science Run 6 And Virgo Science Runs 2 And 3, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Search For Gravitational Waves Associated With Gamma-Ray Bursts During Ligo Science Run 6 And Virgo Science Runs 2 And 3, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the …
Method And Apparatus For Jet-Assisted Drilling Or Cutting, David A. Summers, Klaus Woelk, Kenneth Doyle Oglesby, Greg Galecki
Method And Apparatus For Jet-Assisted Drilling Or Cutting, David A. Summers, Klaus Woelk, Kenneth Doyle Oglesby, Greg Galecki
Mining Engineering Faculty Research & Creative Works
An abrasive cutting or drilling system, apparatus and method, which includes an upstream supercritical fluid and/or liquid carrier fluid, abrasive particles, a nozzle and a gaseous or low-density supercritical fluid exhaust abrasive stream. The nozzle includes a throat section and, optionally, a converging inlet section, a divergent discharge section, and a feed section.
Spectroscopy And Dynamics Of The Predissociated, Quasi-Linear S₂ State Of Chlorocarbene, Chong Tao, Craig A. Richmond, Calvin Mukarakate, Scott H. Kable, George B. Bacskay, Eric C. Brown, Richard Dawes, Phalgun Lolur, Scott A. Reid
Spectroscopy And Dynamics Of The Predissociated, Quasi-Linear S₂ State Of Chlorocarbene, Chong Tao, Craig A. Richmond, Calvin Mukarakate, Scott H. Kable, George B. Bacskay, Eric C. Brown, Richard Dawes, Phalgun Lolur, Scott A. Reid
Chemistry Faculty Research & Creative Works
In this work, we report on the spectroscopy and dynamics of the quasi-linear S2 state of chlorocarbene, CHCl, and its deuterated isotopologue using optical-optical double resonance (OODR) spectroscopy through selected rovibronic levels of the S1 state. This study, which represents the first observation of the S2 state in CHCl, builds upon our recent examination of the corresponding state in CHF, where pronounced mode specificity was observed in the dynamics, with predissociation rates larger for levels containing bending excitation. In the present work, a total of 14 S2 state vibrational levels with angular momentum 1 were observed …
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.
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.
A New Model For The Spectral Induced Polarization Signature Of Bacterial Growth In Porous Media, Andre Revil, Estella A. Atekwana, C. Zhang, Abderrahim Jardani, Schaun M. Smith
A New Model For The Spectral Induced Polarization Signature Of Bacterial Growth In Porous Media, Andre Revil, Estella A. Atekwana, C. Zhang, Abderrahim Jardani, Schaun M. Smith
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The complex conductivity of porous materials and colloidal suspensions comprises two components: an in-phase conductivity associated with electromigration of the charge carriers and a quadrature conductivity associated with the reversible storage of the charges at some polarization length scales. We developed a quantitative model to investigate the frequency domain induced polarization response of suspensions of bacteria and bacteria growth in porous media. Induced polarization of bacteria (α polarization) is related to the properties of the electrical double layer of the bacteria. Surface conductivity and α polarization are due to the Stern layer of counterions occurring in a brush of polymers …
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
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
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 …
Dynamical Reaction Pathways In Eley-Rideal Recombination Of Nitrogen From W(100), Ernesto Quintas-Sánchez, P. Larrégaray, C. Crespos, L. Martin-Gondre, J. Rubayo-Soneira, J. C. Rayez
Dynamical Reaction Pathways In Eley-Rideal Recombination Of Nitrogen From W(100), Ernesto Quintas-Sánchez, P. Larrégaray, C. Crespos, L. Martin-Gondre, J. Rubayo-Soneira, J. C. Rayez
Chemistry Faculty Research & Creative Works
The scattering of atomic nitrogen over a N-pre-adsorbed W(100) surface is theoretically described in the case of normal incidence off a single adsorbate. Dynamical reaction mechanisms, in particular Eley-Rideal (ER) abstraction, are scrutinized in the 0.1-3.0 eV collision energy range and the influence of temperature on reactivity is considered between 300 and 1500 K. Dynamics simulations suggest that, though non-activated reaction pathways exist, the abstraction process exhibits a significant collision energy threshold (0.5 eV). Such a feature, which has not been reported so far in the literature, is the consequence of a repulsive interaction between the impinging and the pre-adsorbed …
An Efficient Second Order In Time Scheme For Approximating Long Time Statistical Properties Of The Two Dimensional Navier-Stokes Equations, Xiaoming Wang
Mathematics and Statistics Faculty Research & Creative Works
We investigate the long-time behavior of the following efficient second order in time scheme for the 2D Navier-Stokes equations in a periodic box: The scheme is a combination of a 2nd-order in time backward-differentiation and a particular explicit Adams-Bashforth treatment of the advection term. Therefore, only a linear constant coefficient Poisson solver is needed at each time step. We prove uniform in time bounds on this scheme in L 2, H per1 and H per2 provided that the time-step is sufficiently small. These time uniform estimates further lead to the convergence of long-time statistics (stationary statistical properties) of the scheme …
Erratum: Triple Compton Effect: A Photon Splitting Into Three Upon Collision With A Free Electron (Physical Review Letters (2012) 108 (233201)), Erik Loetstedt, Ulrich D. Jentschura
Erratum: Triple Compton Effect: A Photon Splitting Into Three Upon Collision With A Free Electron (Physical Review Letters (2012) 108 (233201)), Erik Loetstedt, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
No abstract provided.
Composition-Dependent Oxygen Vacancy Formation In Multicomponent Wide-Band-Gap Oxides, Altynbek Murat, Julia E. Medvedeva
Composition-Dependent Oxygen Vacancy Formation In Multicomponent Wide-Band-Gap Oxides, Altynbek Murat, Julia E. Medvedeva
Physics Faculty Research & Creative Works
The formation and distribution of oxygen vacancy in layered multicomponent InAMO 4 oxides with A3 +=Al or Ga and M2 +=Ca or Zn and in the corresponding binary oxide constituents is investigated using first-principles density functional calculations. Comparing the calculated formation energies of the oxygen defect at six different site locations within the structurally and chemically distinct layers of InAMO 4 oxides, we find that the vacancy distribution is significantly affected not only by the strength of the metal-oxygen bonding, but also by the cation's ability to adjust to anisotropic oxygen environment created by the vacancy. In particular, …
Percolation Transition In Quantum Ising And Rotor Models With Sub-Ohmic Dissipation, Manal Al-Ali, Jose Abel Hoyos, Thomas Vojta
Percolation Transition In Quantum Ising And Rotor Models With Sub-Ohmic Dissipation, Manal Al-Ali, Jose Abel Hoyos, Thomas Vojta
Physics Faculty Research & Creative Works
We investigate the influence of sub-Ohmic dissipation on randomly diluted quantum Ising and rotor models. The dissipation causes the quantum dynamics of sufficiently large percolation clusters to freeze completely. As a result, the zero-temperature quantum phase transition across the lattice percolation threshold separates an unusual super-paramagnetic cluster phase from an inhomogeneous ferromagnetic phase. We determine the low-temperature thermodynamic behavior in both phases, which is dominated by large frozen and slowly fluctuating percolation clusters. We relate our results to the smeared transition scenario for disordered quantum phase transitions, and we compare the cases of sub-Ohmic, Ohmic, and super-Ohmic dissipation.
Quantum Electrodynamic Corrections To The G Factor Of Helium P States, Mariusz Puchalski, Ulrich D. Jentschura
Quantum Electrodynamic Corrections To The G Factor Of Helium P States, Mariusz Puchalski, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The Landég factor describes the response of an atomic energy level to an external perturbation by a uniform and constant magnetic field. In the case of many-electron systems, the leading term is given by the interaction μ B(L- +2S- )•B- , where L- and S- are the orbital and spin angular momentum operators, respectively, summed over all electrons. For helium, a long-standing experimental-theoretical discrepancy for P states motivates a re-evaluation of the higher order terms which follow from relativistic quantum theory and quantum electrodynamics (QED). The tensor structure of relativistic corrections involves scalar, vector, and symmetric and antisymmetric tensor …
Three-Body Dynamics In Single Ionization Of Atomic Hydrogen By 75 Kev Proton Impact, Aaron Laforge, Kisra Egodapitiya, Sachin Sharma, Michael Schulz
Three-Body Dynamics In Single Ionization Of Atomic Hydrogen By 75 Kev Proton Impact, Aaron Laforge, Kisra Egodapitiya, Sachin Sharma, Michael Schulz
Physics Faculty Research & Creative Works
We have measured and calculated doubly differential cross sections for ionization of atomic hydrogen using 75-keV proton impact for fixed projectile energy losses as a function of scattering angle.
Projectile Coherence Effects In Electron Capture By Protons Colliding With H₂ And He, Sachin D. Sharma, Ahmad Hasan, Kisra N. Egodapitiya, T. P. Arthanayaka, G. Sakhelashvili, Michael Schulz
Projectile Coherence Effects In Electron Capture By Protons Colliding With H₂ And He, Sachin D. Sharma, Ahmad Hasan, Kisra N. Egodapitiya, T. P. Arthanayaka, G. Sakhelashvili, Michael Schulz
Physics Faculty Research & Creative Works
We have measured differential cross sections for single and dissociative capture for 25 and 75 keV protons colliding with H2 and He. Significant differences were found depending on whether the projectile beam was coherent or incoherent. For 75 keV p+H2 these differences can be mostly associated with molecular two-center interference and possibly some contributions from path interference. For 25 keV (both targets) they are mostly due to path interference between different impact parameters leading to the same scattering angles and, for the H2 target, possibly some contributions from molecular two-center interference.
Conditions For Extracting Photoionization Cross Sections From Laser-Induced High-Order-Harmonic Spectra, Guoli Wang, Cheng Jin, Anh-Thu Le, C. D. Lin
Conditions For Extracting Photoionization Cross Sections From Laser-Induced High-Order-Harmonic Spectra, Guoli Wang, Cheng Jin, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We show that photoionization cross sections of atoms can be accurately extracted from the high-order-harmonic spectra generated by intense infrared lasers only if the degree of ionization in the gas medium is small, implying that for this purpose the high-order-harmonic generation spectra should be taken at low gas pressure and at low laser intensity experimentally.
Implications For The Origin Of Grb 051103 From Ligo Observations, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Implications For The Origin Of Grb 051103 From Ligo Observations, J. Abadie, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at a distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB …