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Full-Text Articles in Physical Sciences and Mathematics

Control Of Mesoscopic Transport By Modifying Transmission Channels In Opaque Media, Raktim Sarma, Alexey Yamilov, Seng Fatt Liew, Mikhael Guy, Hui Cao Dec 2015

Control Of Mesoscopic Transport By Modifying Transmission Channels In Opaque Media, Raktim Sarma, Alexey Yamilov, Seng Fatt Liew, Mikhael Guy, Hui Cao

Physics Faculty Research & Creative Works

While controlling particle diffusion in a confined geometry is a popular approach taken by both natural and artificial systems, it has not been widely adopted for controlling light transport in random media, where wave interference effects play a critical role. The transmission eigenchannels determine not only light propagation through the disordered system but also the energy concentrated inside. Here, we propose and demonstrate an effective approach to modify these channels, whose structures are considered to be universal in conventional diffusive waveguides. By adjusting the waveguide geometry, we are able to alter the spatial profiles of the transmission eigenchannels significantly and ...


Using Geometry To Manipulate Long-Range Correlation Of Light Inside Disordered Media, Raktim Sarma, Alexey Yamilov, Pauf Neupane, Hui Cao Nov 2015

Using Geometry To Manipulate Long-Range Correlation Of Light Inside Disordered Media, Raktim Sarma, Alexey Yamilov, Pauf Neupane, Hui Cao

Physics Faculty Research & Creative Works

We demonstrate an effective approach of modifying the long-range spatial correlation for light propagating inside random photonic waveguides by varying the shape of the waveguide. The functional form of spatial correlation is no longer universal in the regime of diffusive transport and becomes shape dependent due to the nonlocal nature of wave propagation. The spatial dependence of the correlation may become asymmetric for light incident from opposite ends of the waveguide. This work opens the door to control nonlocal effects in mesoscopic transport of waves by tailoring the geometry of random systems. .


Bounds On Large Extra Dimensions From The Simulation Of Black Hole Events At The Lhc, Shaoqi Hou, Benjamin Harms, Marco Cavaglia Nov 2015

Bounds On Large Extra Dimensions From The Simulation Of Black Hole Events At The Lhc, Shaoqi Hou, Benjamin Harms, Marco Cavaglia

Physics Faculty Research & Creative Works

If large extra dimensions exist, the Planck scale may be as low as a TeV and microscopic black holes may be produced in high-energy particle collisions at this energy scale. We simulate microscopic black hole formation at the Large Hadron Collider and compare the simulation results with recent experimental data by the Compact Muon Solenoid collaboration. The absence of observed black hole events in the experimental data allows us to set lower bounds on the Planck scale and various parameters related to microscopic black hole formation for a number (3 − 6) of extra dimensions. Our analysis sets lower bounds on ...


Infinite-Noise Criticality: Nonequilibrium Phase Transitions In Fluctuating Environments, Thomas Vojta, José A. Hoyos Nov 2015

Infinite-Noise Criticality: Nonequilibrium Phase Transitions In Fluctuating Environments, Thomas Vojta, José A. Hoyos

Physics Faculty Research & Creative Works

We study the effects of time-varying environmental noise on nonequilibrium phase transitions in spreading and growth processes. Using the examples of the logistic evolution equation as well as the contact process, we show that such temporal disorder gives rise to a distinct type of critical points at which the effective noise amplitude diverges on long time scales. This leads to enormous density fluctuations characterized by an infinitely broad probability distribution at criticality. We develop a real-time renormalization-group theory that provides a general framework for the effects of temporal disorder on nonequilibrium processes. We also discuss how general this exotic critical ...


The Stripe 82 Massive Galaxy Project. I. Catalog Construction, Kevin Bundy, Alexie Leauthaud, Shun Saito, For Full List Of Authors, See Publisher's Website. Nov 2015

The Stripe 82 Massive Galaxy Project. I. Catalog Construction, Kevin Bundy, Alexie Leauthaud, Shun Saito, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The Stripe 82 Massive Galaxy Catalog (S82-MGC) is the largest-volume stellar mass-limited sample of galaxies beyond z ≈ 0.1 constructed to date. Spanning 139.4 deg2, the S82-MGC includes a mass-limited sample of 41,770 galaxies with log M*/M ≳ 11.2 to z ≈ 0.7, sampling a volume of 0.3 Gpc3, roughly equivalent to the volume of the Sloan Digital Sky Survey-I/II (SDSS-I/II) z < 0.15 main sample. The catalog is built on three pillars of survey data: the SDSS Stripe 82 Coadd photometry which reaches r-band magnitudes of ∼23.5 AB, Y JHK photometry at depths of 20th magnitude (AB) from the UK Infrared Deep Sky Survey Large Area Survey, and over 70,000 spectroscopic galaxy redshifts from the SDSS-I/II and the Baryon Oscillation Spectroscopic Survey. We describe the catalog construction and verification, the production of 9-band matched aperture photometry, tests of existing and newly estimated photometric redshifts required to supplement spectroscopic redshifts for 55% of the log M*/M ≳ 11.2 sample, and geometric masking. We provide near-IR based stellar mass estimates and compare these to previous estimates. All catalog products are made publicly available. The S82-MGC not ...


Comparison Of Experimental And Theoretical Electron-Impact-Ionization Triple-Differential Cross Sections For Ethane, Esam Ali, Kate Nixon, Andrw Murray, Chuangang Ning, James Colgan, Don H. Madison Oct 2015

Comparison Of Experimental And Theoretical Electron-Impact-Ionization Triple-Differential Cross Sections For Ethane, Esam Ali, Kate Nixon, Andrw Murray, Chuangang Ning, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We have recently examined electron-impact ionization of molecules that have one large atom at the center, surrounded by H nuclei (H2O, NH3, CH4). All of these molecules have ten electrons; however, they vary in their molecular symmetry. We found that the triple-differential cross sections (TDCSs) for the highest occupied molecular orbitals (HOMOs) were similar, as was the character of the HOMO orbitals which had a p-type "peanut" shape. In this work, we examine ethane (C2H6) which is a molecule that has two large atoms surrounded by H nuclei, so that its HOMO has ...


Reconstruction Of Two-Dimensional Molecular Structure With Laser-Induced Electron Diffraction From Laser-Aligned Polyatomic Molecules, Chao Yu, Hui Wei, Xu Wang, Anh-Thu Le, Ruifeng Lu, C. D. Lin Oct 2015

Reconstruction Of Two-Dimensional Molecular Structure With Laser-Induced Electron Diffraction From Laser-Aligned Polyatomic Molecules, Chao Yu, Hui Wei, Xu Wang, Anh-Thu Le, Ruifeng Lu, C. D. Lin

Physics Faculty Research & Creative Works

Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics. Based on laser-induced electron diffraction and partial one-dimensional molecular alignment, here we provide two effective methods for reconstructing two-dimensional structure of polyatomic molecules. We demonstrate that electron diffraction images in both scattering angles and broadband energy can be utilized to retrieve complementary structure information, including positions of light atoms. With picometre spatial resolution and the inherent femtosecond temporal resolution of lasers, laser-induced electron diffraction method offers significant opportunities for probing atomic motion in a large molecule in a typical pump-probe measurement.


Polyatomic Molecular Structure Retrieval Using Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, M. Sclafani, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert Sep 2015

Polyatomic Molecular Structure Retrieval Using Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, M. Sclafani, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert

Physics Faculty Research & Creative Works

Laser-induced electron diffraction is a developing dynamical imaging technique that is already able to probe molecular dynamics at few-femtosecond temporal resolutions and has the potential to reach the sub-femtosecond level. Here we provide the recipe for the extension of the technique to polyatomic molecules and we demonstrate the method by extracting the structure of aligned and anti-aligned acetylene (C₂H₂). We show that multiple bond lengths can be simultaneously imaged at high accuracy including elusive hydrogen containing bonds. Our results open the door to the investigation of larger complex molecules and the realization of a true molecular movie.


Low-Energy (E₀ = 65 Ev) Electron-Impact Ionization Of Neon: Internormalized Triple-Differentical Cross Sections In 3d Kinematics, Xueguang Ren, Sadek M. Amami, Oleg I. Zatsarinny, Thomas Pfluger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn Sep 2015

Low-Energy (E₀ = 65 Ev) Electron-Impact Ionization Of Neon: Internormalized Triple-Differentical Cross Sections In 3d Kinematics, Xueguang Ren, Sadek M. Amami, Oleg I. Zatsarinny, Thomas Pfluger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn

Physics Faculty Research & Creative Works

We present a combined experimental and theoretical study on the low-energy (E0 = 65 eV) electron- impact ionization of neon. The experimental data are compared to predictions from a hybrid second-order distorted-wave Born plus R-matrix approach (DWB2-RM), the distorted-wave Born approximation with inclusion of post-collision interaction (DWBA-PCI), a three-body distorted-wave approach (3DW), and a B-spline R-matrix (BSR) with pseudostates approach. Excellent agreement is found between experiment and the 3DW and BSR theories. The importance of PCI effects is clearly visible in this low-energy electron-impact ionization process.


Theoretical And Experimental Study Of (E,2e) Ionization Of The Co₂ (1ΠG) Molecule At 250 Ev, Mevlut Dogan, Zehra Nur Ozer, Murat Yavuz, Osman Alwan, Adnan Naja, Boghos B. Joulakian, Esam S M Ali, Chuangang Ning, Don H. Madison Sep 2015

Theoretical And Experimental Study Of (E,2e) Ionization Of The Co₂ (1ΠG) Molecule At 250 Ev, Mevlut Dogan, Zehra Nur Ozer, Murat Yavuz, Osman Alwan, Adnan Naja, Boghos B. Joulakian, Esam S M Ali, Chuangang Ning, Don H. Madison

Physics Faculty Research & Creative Works

Triple differential cross sections (TDCSs) of the electron-impact ionization of carbon dioxide are measured in the coplanar asymmetric geometry, with incident electron energy value of 250eV, and ejected electron of 37eV. We will report the experimental results in comparison with the theoretical calculations of the M3DW and TCC (type 5) calculations.


Evidence For Unnatural-Parity Contributions To Electron-Impact Ionization Of Laser-Aligned Atoms, G. S. J. Armstrong, J. Colgan, M. S. Pindzola, S. Amami, Don H. Madison, J. Pursehouse, K. L. Nixon, A. J. Murray Sep 2015

Evidence For Unnatural-Parity Contributions To Electron-Impact Ionization Of Laser-Aligned Atoms, G. S. J. Armstrong, J. Colgan, M. S. Pindzola, S. Amami, Don H. Madison, J. Pursehouse, K. L. Nixon, A. J. Murray

Physics Faculty Research & Creative Works

Recent measurements have examined the electron-impact ionization of excited-state laser-aligned Mg atoms. In this work we show that the ionization cross section arising from the geometry where the aligned atom is perpendicular to the scattering plane directly probes the unnatural parity contributions to the ionization amplitude. The contributions from natural parity partial waves cancel exactly in this geometry. Our calculations resolve the discrepancy between the nonzero measured cross sections in this plane and the zero cross section predicted by distorted-wave approaches. We demonstrate that this is a general feature of ionization from p-state targets by additional studies of ionization from ...


Coplanar Asymmetric Angles And Symmetric Energy Sharing Triple Differential Cross Sections For 200 Ev Electron-Impact Ionization Of Ar (3p), Zehra Nur Ozer, Sadek M. Amami, Onur Varol, Murat Yavuz, Mevlut Dogan, Don H. Madison Sep 2015

Coplanar Asymmetric Angles And Symmetric Energy Sharing Triple Differential Cross Sections For 200 Ev Electron-Impact Ionization Of Ar (3p), Zehra Nur Ozer, Sadek M. Amami, Onur Varol, Murat Yavuz, Mevlut Dogan, Don H. Madison

Physics Faculty Research & Creative Works

We have measured triple differential cross sections (TDCSs) for electron-impact ionization of the 3p shell of Ar at 200 eV incident electron energy. The experiments have been performed in coplanar asymmetric energy sharing geometry. The experimental results are compared with the theoretical models of three body distorted wave (3DW) and distorted wave Born approximation (DWBA).


First Evidence Of Interference Effects In The Ionization Of N₂ Molecule, Zehra Nur Ozer, Hari Chaluvadi, Mevlut Dogan, James Colgan, Don H. Madison Sep 2015

First Evidence Of Interference Effects In The Ionization Of N₂ Molecule, Zehra Nur Ozer, Hari Chaluvadi, Mevlut Dogan, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We will present an experimental and theoretical investigation of triple differential cross sections for electron- impact ionization of nitrogen molecules at intermediate energies. A discussion of interference effects contained in the theoretical and experimental interference factors will be presented.


Anharmonic Properties In Mg₂X (X= C, Si, Ge, Sn, Pb) From First-Principles Calculations, Aleksandr V. Chernatynskiy, Simon R. Phillpot Aug 2015

Anharmonic Properties In Mg₂X (X= C, Si, Ge, Sn, Pb) From First-Principles Calculations, Aleksandr V. Chernatynskiy, Simon R. Phillpot

Physics Faculty Research & Creative Works

Thermal conductivity reduction is one of the potential routes to improve the performance of thermoelectric materials. However, detailed understanding of the thermal transport of many promising materials is still missing. In this paper, we employ electronic-structure calculations at the level of density functional theory to elucidate thermal transport properties of the Mg2X (X=C, Si, Ge, Sn, and Pb) family of compounds, which includes Mg2Si, a material already identified as a potential thermoelectric. All these materials crystallize into the same antifluorite structure. Systematic trends in the anharmonic properties of these materials are presented and examined. Our ...


Muonic Bound Systems, Virtual Particles, And Proton Radius, Ulrich D. Jentschura Jul 2015

Muonic Bound Systems, Virtual Particles, And Proton Radius, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

The proton radius puzzle questions the self-consistency of theory and experiment in light muonic and electronic bound systems. Here we summarize the current status of virtual particle models as well as Lorentz-violating models that have been proposed in order to explain the discrepancy. Highly charged one-electron ions and muonic bound systems have been used as probes of the strongest electromagnetic fields achievable in the laboratory. The average electric field seen by a muon orbiting a proton is comparable to hydrogenlike uranium and, notably, larger than the electric field in the most advanced strong-laser facilities. Effective interactions due to virtual annihilation ...


Interference Effects For Intermediate Energy Electron-Impact Ionization Of H₂ And N₂ Molecules, Zehra Nur Ozer, Hari Chaluvadi, Don H. Madison, Mevlut Dogan Jul 2015

Interference Effects For Intermediate Energy Electron-Impact Ionization Of H₂ And N₂ Molecules, Zehra Nur Ozer, Hari Chaluvadi, Don H. Madison, Mevlut Dogan

Physics Faculty Research & Creative Works

We have studied electron impact ionization of H2 and N2 molecules at intermediate energies to look for possible two center interference effects experimentally and theoretically. Here we report a study of the interference factor I for 250 eV electron-impact ionization. The experimental measurements are performed using a crossed-beam-type electron-electron coincidence spectrometer and theoretical calculations are obtained using the Molecular Three Body Distorted Wave Approximation (M3DW). We found that the I-factor demonstrated strong evidence for two-center interference effects for both H2 and N2. We also found that the I-factor is more sensitive to projectile angular scans than ...


Applicability Of The Position-Dependent Diffusion Approach To Localized Transport Through Disordered Waveguides, Pauf Neupane, Alexey Yamilov Jul 2015

Applicability Of The Position-Dependent Diffusion Approach To Localized Transport Through Disordered Waveguides, Pauf Neupane, Alexey Yamilov

Physics Faculty Research & Creative Works

In this work we show analytically and numerically that the localized regime of wave transport can be modeled as position-dependent diffusion with a diffusion coefficient that retains the memory of the source location. The dependence on the source diminishes when absorption is introduced.


Erratum: Low-Energy Electron-Impact Ionization Of Argon: Three-Dimensional Cross Section (Physical Review A - Atomic, Molecular, And Optical Physics 85, 032702 (2012)), Xueguang Ren, Thomas Pfluger, Joachim Hermann Ullrich, Oleg I. Zatsarinny, Klaus Bartschat, Don H. Madison, Alexander Dorn Jul 2015

Erratum: Low-Energy Electron-Impact Ionization Of Argon: Three-Dimensional Cross Section (Physical Review A - Atomic, Molecular, And Optical Physics 85, 032702 (2012)), Xueguang Ren, Thomas Pfluger, Joachim Hermann Ullrich, Oleg I. Zatsarinny, Klaus Bartschat, Don H. Madison, Alexander Dorn

Physics Faculty Research & Creative Works

No abstract provided.


Ultrarelativistic Decoupling Transformation For Generalized Dirac Equations, J. H. Noble, Ulrich D. Jentschura Jul 2015

Ultrarelativistic Decoupling Transformation For Generalized Dirac Equations, J. H. Noble, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

The Foldy-Wouthuysen transformation is known to uncover the nonrelativistic limit of a generalized Dirac Hamiltonian, lending an intuitive physical interpretation to the effective operators within Schrö dinger-Pauli theory. We here discuss the opposite, ultrarelativistic limit which requires the use of a fundamentally different expansion where the leading kinetic term in the Dirac equation is perturbed by the mass of the particle and other interaction (potential) terms, rather than vice versa. The ultrarelativistic decoupling transformation is applied to free Dirac particles (in the Weyl basis) and to high-energy tachyons, which are faster-than-light particles described by a fully Lorentz-covariant equation. The effective ...


Emerging Criticality In The Disordered Three-Color Ashkin-Teller Model, Qiong Zhu, Xin Wan, Rajesh Narayanan, José A. Hoyos, Thomas Vojta Jun 2015

Emerging Criticality In The Disordered Three-Color Ashkin-Teller Model, Qiong Zhu, Xin Wan, Rajesh Narayanan, José A. Hoyos, Thomas Vojta

Physics Faculty Research & Creative Works

We study the effects of quenched disorder on the first-order phase transition in the two-dimensional three-color Ashkin-Teller model by means of large-scale Monte Carlo simulations. We demonstrate that the first-order phase transition is rounded by the disorder and turns into a continuous one. Using a careful finite-size-scaling analysis, we provide strong evidence for the emerging critical behavior of the disordered Ashkin-Teller model to be in the clean two-dimensional Ising universality class, accompanied by universal logarithmic corrections. This agrees with perturbative renormalization-group predictions by Cardy. As a byproduct, we also provide support for the strong-universality scenario for the critical behavior of ...


Imaging An Aligned Polyatomic Molecule With Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert Jun 2015

Imaging An Aligned Polyatomic Molecule With Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert

Physics Faculty Research & Creative Works

Laser-induced electron diffraction is an evolving tabletop method that aims to image ultrafast structural changes in gas-phase polyatomic molecules with sub-Ångström spatial and femtosecond temporal resolutions. Here we demonstrate the retrieval of multiple bond lengths from a polyatomic molecule by simultaneously measuring the C-C and C-H bond lengths in aligned acetylene. Our approach takes the method beyond the hitherto achieved imaging of simple diatomic molecules and is based on the combination of a 160kHz mid-infrared few-cycle laser source with full three-dimensional electron-ion coincidence detection. Our technique provides an accessible and robust route towards imaging ultrafast processes in complex gas-phase molecules ...


Erratum: Theoretical And Experimental (E,2e) Study Of Electron-Impact Ionization Of Laser-Aligned Mg Atoms [Physical Review A 90, 062707 (2014)], Sadek Amami, Andrew J. Murray, Al Stauffer, Kate Nixon, Gregory Armstrong, James Colgan, Don H. Madison Jun 2015

Erratum: Theoretical And Experimental (E,2e) Study Of Electron-Impact Ionization Of Laser-Aligned Mg Atoms [Physical Review A 90, 062707 (2014)], Sadek Amami, Andrew J. Murray, Al Stauffer, Kate Nixon, Gregory Armstrong, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We have recently reported a theoretical and experimental study of electron-impact ionization of laser-aligned magnesium. Results were presented for both ionization of the ground state, as well as for laser-aligned atoms in the 3p state. For ionization from the 3p state, theoretical results were presented using the distorted wave Born (DWBA) and three-body distorted wave (3DW) approximations. Unfortunately, after publication we learned that the theoretical results were incorrect due to one of the arrays in the computer code dimensioned too small. The figures affected by this error are Figs. 3–5 in the original paper. The present Figs ...


Critical States Embedded In The Continuum, Milan Koirala, Alexey Yamilov, A. Basiri, Yaron Bromberg, Hui Cao, Tsampikos Kottos May 2015

Critical States Embedded In The Continuum, Milan Koirala, Alexey Yamilov, A. Basiri, Yaron Bromberg, Hui Cao, Tsampikos Kottos

Physics Faculty Research & Creative Works

Weintroduce a class of critical states which are embedded in the continuum (CSC) of a one-dimensional optical waveguide array with one non-Hermitian defect. These states are on the verge of being fractal and have real propagation constants. They emerge at a phase transition which is driven by the imaginary refractive index of the defective waveguide and it is accompanied by a mode segregation which reveals analogies with the Dicke super-radiance. Below this point the states are extended while above it they evolve to exponentially localized modes. An addition of a background gain or loss can turn these localized states into ...


Tunable Negative Permeability In A Three-Dimensional Superconducting Metamaterial, Cihan Kurter, T. Lan, L. Sarytchev, Steven Mark Anlage May 2015

Tunable Negative Permeability In A Three-Dimensional Superconducting Metamaterial, Cihan Kurter, T. Lan, L. Sarytchev, Steven Mark Anlage

Physics Faculty Research & Creative Works

We report on highly tunable radio-frequency (rf) characteristics of a low-loss and compact three-dimensional (3D) metamaterial made of superconducting thin-film spiral resonators. The rf transmission spectrum of a single element of the metamaterial shows a fundamental resonance peak at ~24.95 MHz that shifts to a 25% smaller frequency and becomes degenerate when a 3D array of such elements is created. The metamaterial shows an in situ tunable narrow frequency band in which the real part of the effective permeability is negative over a wide range of temperature. This narrow frequency band gradually possesses near-zero and positive values for the ...


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 Apr 2015

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 this work, we introduce a classical trajectory Monte Carlo (CTMC) methodology, specially conceived to provide a more accurate representation of charge-exchange processes between highly charged ions and H(1s) and H* (n=2). These processes are of particular relevance in power fusion reactor programs, for which charge-exchange spectroscopy has become a useful plasma diagnostics tool. To test the methodology, electron-capture reactions from these targets by C6+,N7+, and O8+ are studied at impact energies in the 10-150keV/amu range. State-selective cross sections are contrasted with those predicted by the standard microcanonical formulation of the CTMC method ...


Target Electron Ionization In Li²⁺-L-Li Collisions: A Multi-Electron Perspective, Maciej Dominik Piewanowski, Laszlo Gulyas, Marko W. Horbatsch, Johannes Goullon, Natalia Ferreira, Renate Hubele, Vitor L B D De Jesus, H. Lindenblatt, Katharina R. Schneider, Michael Schulz, Michael Schuricke, Z. Song, Shaofeng Zhang, Daniel Fischer, Tom Kirchner Apr 2015

Target Electron Ionization In Li²⁺-L-Li Collisions: A Multi-Electron Perspective, Maciej Dominik Piewanowski, Laszlo Gulyas, Marko W. Horbatsch, Johannes Goullon, Natalia Ferreira, Renate Hubele, Vitor L B D De Jesus, H. Lindenblatt, Katharina R. Schneider, Michael Schulz, Michael Schuricke, Z. Song, Shaofeng Zhang, Daniel Fischer, Tom Kirchner

Physics Faculty Research & Creative Works

Target electron removal in Li2+-Li collisions at 2290 keV/amu is studied experimentally and theoretically for ground and excited lithium target configurations. It is shown that in outer-shell ionization a single-electron process plays the dominant part. However, the K-shell ionization results are more difficult to interpret. According to our calculations, the process is shown to be strongly single-particle like. On one hand, a high resemblance between theoretical single-particle ionization and exclusive inner-shell ionization is demonstrated, and contributions from multi-electron processes are found to be weak. On the other hand, it is indicated by the discrepancy between experimental and ...


Luminous Red Galaxies In Clusters: Central Occupation, Spatial Distributions And Miscentring, Hanako Hoshino, Alexie Leauthaud, Shun Saito, For Full List Of Authors, See Publisher's Website. Apr 2015

Luminous Red Galaxies In Clusters: Central Occupation, Spatial Distributions And Miscentring, Hanako Hoshino, Alexie Leauthaud, Shun Saito, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Luminous red galaxies (LRG) from the Sloan Digital Sky Survey are among the best understood samples of galaxies and are employed in a broad range of cosmological studies. In this paper, we study how LRGs occupy massive haloes via counts in clusters and reveal several unexpected trends. Using the red-sequence Matched-filter Probabilistic Percolation (redMaPPer) cluster catalogue, we derive the central occupation of LRGs as a function richness. We show that clusters contain a significantly lower fraction of central LRGs than predicted from the two-point correlation function. At halo masses of 1014.5 M, we find Ncen = 0.73 ...


Kinematically Complete Study Of Low-Energy Electron-Impact Ionization Of Neon: Internormalized Cross Sections In Three-Dimensional Kinematics, Xueguang Ren, Sadek Amami, Oleg Zatsarinny, Thomas Pflüger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn Mar 2015

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

Physics Faculty Research & Creative Works

Low-energy (E0 0=65eV) electron-impact single ionization of Ne (2p) has been investigated to thoroughly test state-of-the-art theoretical approaches. The experimental data were measured using a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission energies ranging from 2 to 8 eV, and projectile scattering angles ranging from 8.5⁰ to 20.0⁰. The experimental triple-differential cross sections are internormalized across all measured scattering angles and ejected energies. The experimental data are compared to predictions from a hybrid second-order distorted-wave Born plus R-matrix approach, the distorted-wave Born approximation with the inclusion of ...


Directed Search For Gravitational Waves From Scorpius X-1 With Initial Ligo Data, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Mar 2015

Directed Search For Gravitational Waves From Scorpius X-1 With Initial Ligo Data, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present results of a search for continuously emitted gravitational radiation, directed at the brightest low-mass x-ray binary, Scorpius X-1. Our semicoherent analysis covers 10 days of LIGO S5 data ranging from 50-550 Hz, and performs an incoherent sum of coherent F-statistic power distributed amongst frequency-modulated orbital sidebands. All candidates not removed at the veto stage were found to be consistent with noise at a 1% false alarm rate. We present Bayesian 95% confidence upper limits on gravitational-wave strain amplitude using two different prior distributions: a standard one, with no a priori assumptions about the orientation of Scorpius X-1 ...


Benchmarking Accurate Spectral Phase Retrieval Of Single Attosecond Pulses, Hui Wei, Anh-Thu Le, Toru Morishita, Chao Yu, C. D. Lin Feb 2015

Benchmarking Accurate Spectral Phase Retrieval Of Single Attosecond Pulses, Hui Wei, Anh-Thu Le, Toru Morishita, Chao Yu, C. D. Lin

Physics Faculty Research & Creative Works

A single extreme-ultraviolet (XUV) attosecond pulse or pulse train in the time domain is fully characterized if its spectral amplitude and phase are both determined. The spectral amplitude can be easily obtained from photoionization of simple atoms where accurate photoionization cross sections have been measured from, e.g., synchrotron radiations. To determine the spectral phase, at present the standard method is to carry out XUV photoionization in the presence of a dressing infrared (IR) laser. In this work, we examine the accuracy of current phase retrieval methods (PROOF and iPROOF) where the dressing IR is relatively weak such that photoelectron ...