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2003

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Full-Text Articles in Physics

Pion-Kaon Correlations In Central Au+Au Collisions At √SNn=130 Gev, Star Collaboration, T.D. Gutierrez Dec 2003

Pion-Kaon Correlations In Central Au+Au Collisions At √SNn=130 Gev, Star Collaboration, T.D. Gutierrez

Physics

Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at √sNN=130  GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.


Anomaly In Conformal Quantum Mechanics: From Molecular Physics To Black Holes, Horacio E. Camblong Dec 2003

Anomaly In Conformal Quantum Mechanics: From Molecular Physics To Black Holes, Horacio E. Camblong

Physics and Astronomy

A number of physical systems exhibit a particular form of asymptotic conformal invariance: within a particular domain of distances, they are characterized by a long-range conformal interaction (inverse square potential), the apparent absence of dimensional scales, and an SO(2,1) symmetry algebra. Examples from molecular physics to black holes are provided and discussed within a unified treatment. When such systems are physically realized in the appropriate strong-coupling regime, the occurrence of quantum symmetry breaking is possible. This anomaly is revealed by the failure of the symmetry generators to close the algebra in a manner shown to be independent of ...


Three-Pion Hanbury Brown–Twiss Correlations In Relativistic Heavy-Ion Collisions From The Star Experiment, Star Collaboration, T.D. Gutierrez Dec 2003

Three-Pion Hanbury Brown–Twiss Correlations In Relativistic Heavy-Ion Collisions From The Star Experiment, Star Collaboration, T.D. Gutierrez

Physics

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at √sNN=130   GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.


Projectile-Shape Dependence Of Impact Craters In Loose Granular Media, K. A. Newhall Dec 2003

Projectile-Shape Dependence Of Impact Craters In Loose Granular Media, K. A. Newhall

Department of Physics Papers

We report on the penetration of cylindrical projectiles dropped from rest into a dry, noncohesive granular medium. The cylinder length, diameter, density, and tip shape are all explicitly varied. For deep penetrations, as compared to the cylinder diameter, the data collapse onto a single scaling law that varies as the 1/3 power of the total drop distance, the 1/2 power of cylinder length, and the 1/6 power of cylinder diameter. For shallow penetrations, the projectile shape plays a crucial role with sharper objects penetrating deeper.


Resonant Emergence Of Global And Local Spatiotemporal Order In A Nonlinear Field Model, Marcelo Gleiser, Rafael C. Howell Dec 2003

Resonant Emergence Of Global And Local Spatiotemporal Order In A Nonlinear Field Model, Marcelo Gleiser, Rafael C. Howell

Open Dartmouth: Faculty Open Access Scholarship

We investigate the nonequilibrium evolution of a scalar field in (2+1) dimensions. The field is set in a double-well potential in contact (open) or not (closed) with a heat bath. For closed systems, we observe the synchronized emergence of coherent spatiotemporal configurations, identified with oscillons. This initial global ordering degenerates into localized order until all oscillons disappear. We show that the synchronization is driven by resonant parametric oscillations of the field’s zero mode and that local ordering is only possible outside equipartition. None of these orderings occur for open systems.


Fundamental And Magnetic-Hardening Studies Of Rare-Earth And Nanocomposite Magnets, David J. Sellmyer, George C. Hadjipanayis Dec 2003

Fundamental And Magnetic-Hardening Studies Of Rare-Earth And Nanocomposite Magnets, David J. Sellmyer, George C. Hadjipanayis

David Sellmyer Publications

In this project we study new nanocrystalline and nanocomposite structures that have high potential for permanent-magnet development. These materials, which can be synthesized to have either very high or intermediate coercivities, have many applications in electric power, transportation, and information-storage industries. There is great interest in further development of understanding and application of these materials. Following are brief discussions of recent research highlights for the present grant.


Strong Field Detachment Of A Negative Ion With Non-Zero Angular Momentum: Application To F-, M. V. Frolov, N. L. Manakov, E. A. Pronin, Anthony F. Starace Dec 2003

Strong Field Detachment Of A Negative Ion With Non-Zero Angular Momentum: Application To F-, M. V. Frolov, N. L. Manakov, E. A. Pronin, Anthony F. Starace

Anthony F. Starace Publications

We apply our recently developed, model-independent quantum approach for intense laser detachment of a weakly bound electron to interpret a recent experiment on above-threshold detachment (ATD) of the F- ion. We find that the measured electron energies correspond to the “Keldysh part” of the ATD spectrum, just below the onset of our predicted rescattering plateau. Overall, our predicted ATD spectrum (using a scaled peak intensity and focal averaging) is in excellent agreement with the experimental data, except for certain structures observed for electron energies above 12.6 eV that we attribute to known two-electron resonances of F-. A number of ...


Decoherence-Driven Cooling Of A Degenerate Spinor Bose Gas, H. J. Lewandowski, J. M. Mcguirk, D. M. Harber, Eric A. Cornell Dec 2003

Decoherence-Driven Cooling Of A Degenerate Spinor Bose Gas, H. J. Lewandowski, J. M. Mcguirk, D. M. Harber, Eric A. Cornell

Physics Faculty Contributions

We investigate the relationship between the coherence of a partially Bose-condensed spinor gas and its temperature. We observe cooling of the normal component driven by decoherence as well as the effect of temperature on decoherence rates.


Measurement Of Prompt Charm Meson Production Cross Sections In Pp̅ Collisions At √S=1.96 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Dec 2003

Measurement Of Prompt Charm Meson Production Cross Sections In Pp̅ Collisions At √S=1.96 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report on measurements of differential cross sections d /dpT for prompt charm meson production in pp̅ collisions at √s=1.96 TeV using 5.8±0.3 pb-1 of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm meson cross sections are measured in the central rapidity region |y|≤1 in four fully reconstructed decay modes: D0K- π+, D*+→D0 π+, D+K- π+ π+, Ds+→ Φπ+, and their charge conjugates ...


Linear Perturbations In Brane Gas Cosmology, Scott Watson, Robert H. Brandenberger Dec 2003

Linear Perturbations In Brane Gas Cosmology, Scott Watson, Robert H. Brandenberger

Physics

We consider the effect of string inhomogeneities on the time dependent background of Brane Gas Cosmology. We derive the equations governing the linear perturbations of the dilaton-gravity background in the presence of string matter sources. We focus on long wavelength fluctuations and find that there are no instabilities. Thus, the predictions of Brane Gas Cosmology are robust against the introduction of linear perturbations. In particular, we find that the stabilization of the extra dimensions (moduli) remains valid in the presence of dilaton and string perturbations.


United States Patent: Application Of High Spin Polarization Materials In Two Terminal Non-Volatile Bistable Memory Devices, Bernard Doudin, Andrei Sokolov, Cheol-Soo Yang, Lu Yuan, Sy-Hwang Liou Dec 2003

United States Patent: Application Of High Spin Polarization Materials In Two Terminal Non-Volatile Bistable Memory Devices, Bernard Doudin, Andrei Sokolov, Cheol-Soo Yang, Lu Yuan, Sy-Hwang Liou

Si-Hwang Liou Publications

Disclosed are two terminal bistable memory cells having least two high-spin polarization magnetic material junctions which are separated from one another by electron trap site defect containing insulator. The two terminal bistable memory cells demonstrate stable, low current readable, hysteretic resistance states which are set by the flow of a relatively high, (eg. a milliamp or less), plus or minus polarity D.C. current therethrough, which resistance is monitored by lower magnitude A.C. or D.C. current flow therethrough. Preferred cells have at least one Cr02/Cr203/ CrO2 sequence but typically have multiple Cr0 ...


Physics Department News, December 2003, College Of Arts And Sciences Dec 2003

Physics Department News, December 2003, College Of Arts And Sciences

Physics Newsletter

Contents from Volume 2, Issue 2:

  • A Note from the Editor
  • From the Chair
  • What’s New at the University
  • Faculty Highlights
  • Staff Highlights
  • Accelerator Upgrade 5
  • PhysTEC
  • Distinguished Alumni Award
  • Alumni News
  • Recent Guest
  • Goldwater Scholar
  • New Grants
  • Student Awards
  • Recent Graduates
  • Department Roster
  • Photo Gallery
  • Feedback/Update Reply Form


Physica: The Newsletter Of Utep's Department Of Physics, Utep Department Of Physics Dec 2003

Physica: The Newsletter Of Utep's Department Of Physics, Utep Department Of Physics

The Department of Physics

Electronic newsletter of UTEP's Department of Physics, December 2003.


Comparisons Of Electron Fluxes Measured In The Crustal Fields At Mars By The Mgs Magnetometer/Electron Reflectometer Instrument With A B Field-Dependent Transport Code, Michael W. Liemohn, David L. Mitchell, Andrew F. Nagy, Jane L. Fox, Tamara W. Reimer, Yingjuan J. Ma Dec 2003

Comparisons Of Electron Fluxes Measured In The Crustal Fields At Mars By The Mgs Magnetometer/Electron Reflectometer Instrument With A B Field-Dependent Transport Code, Michael W. Liemohn, David L. Mitchell, Andrew F. Nagy, Jane L. Fox, Tamara W. Reimer, Yingjuan J. Ma

Physics Faculty Publications

We compare Mars Global Surveyor (MGS) magnetometer/electron reflectometer data with results from a B field–dependent kinetic transport code for ‘‘superthermal’’ electrons. The photoelectrons created on crustal field loops, when they are on the dayside, allow for the exploration of the magnetic topology and the upper atmospheric density structure. A case study of a typical orbit of the MGS satellite through the strong crustal field region in the southern hemisphere of Mars is examined. The results indicate that the low solar wind dynamic pressure during the selected orbit allowed for the expansion of the crustal field line to relatively ...


Fabrication And Characterization Of N-Zno/P-Algan Heterojunction Light-Emitting Diodes On 6h-Sic Substrates, Y. I. Alivov, E. V. Kalinina, A. E. Cherenkov, David C. Look, B. M. Ataev, A. K. Omaev, M. V. Chukichev, D. M. Bagnall Dec 2003

Fabrication And Characterization Of N-Zno/P-Algan Heterojunction Light-Emitting Diodes On 6h-Sic Substrates, Y. I. Alivov, E. V. Kalinina, A. E. Cherenkov, David C. Look, B. M. Ataev, A. K. Omaev, M. V. Chukichev, D. M. Bagnall

Physics Faculty Publications

We report on the fabrication of n-ZnO/p-AlGaN heterojunction light-emitting diodes on 6H-SiC substrates. Hydride vapor phase epitaxy was used to grow p-type AlGaN, while chemical vapor deposition was used to produce the n-type ZnO layers. Diode-like, rectifying I-V characteristics, with threshold voltage ~3.2 V and low reverse leakage current ~10-7 A, are observed at room temperature. Intense ultraviolet emission with a peak wavelength near 389 nm is observed when the diode is forward biased; this emission is found to be stable at temperatures up to 500 K and shown to originate from recombination within the ZnO.


Isotropic Loop Quantum Cosmology With Matter. Ii. The Lorentzian Constraint, F. Hinterleitner, Seth Major Dec 2003

Isotropic Loop Quantum Cosmology With Matter. Ii. The Lorentzian Constraint, F. Hinterleitner, Seth Major

Articles

The Lorentzian Hamiltonian constraint is solved for isotropic loop quantum cosmology coupled to a massless scalar field. As in the Euclidean case, the discreteness of quantum geometry removes the classical singularity from the quantum Friedmann models. In spite of the absence of the classical singularity, a modified DeWitt initial condition is incompatible with a late-time smooth behavior. Further, the smooth behavior is recovered only for positive or negatives times but not both. An important feature, which is shared with the Euclidean case, is a minimal initial energy of the order of the Planck energy required for the system to evolve ...


Biological Permanent Magnets, Richard B. Frankel Dec 2003

Biological Permanent Magnets, Richard B. Frankel

Physics

Magnetotactic bacteria orient and migrate along magnetic field lines. Each cell is essentially a self-propelled magnetic dipole. The magnetic properties of these bacteria have been determined by a variety of techniques, including pulsed hysteresis measurements on single cells.


Midrapidity Neutral-Pion Production In Proton-Proton Collisions At Root S 200 Gev, S. S. Adler, Sergey Belikov, S. Bhagavatula, Paul Constantin, Nathan C. Grau, John C. Hill, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Jan Rak, Marzia Rosati, F. K. Wohn, Et Al., Phenix Collaboration Dec 2003

Midrapidity Neutral-Pion Production In Proton-Proton Collisions At Root S 200 Gev, S. S. Adler, Sergey Belikov, S. Bhagavatula, Paul Constantin, Nathan C. Grau, John C. Hill, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Jan Rak, Marzia Rosati, F. K. Wohn, Et Al., Phenix Collaboration

Physics and Astronomy Publications

The invariant differential cross section for inclusive neutral-pion production in p+p collisions at root s=200 GeV has been measured at midrapidity (\eta\<0.35) over the range 1 < p(T) less than or similar to 14 GeV/c by the PHENIX experiment at the Relativistic Heavy Ion Collider. Predictions of next-to-leading order perturbative QCD calculations are consistent with these measurements. The precision of our result is sufficient to differentiate between prevailing gluon-to-pion fragmentation functions.


Afci Quarterly Input – Unlv October Through December, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division Dec 2003

Afci Quarterly Input – Unlv October Through December, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.


Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources: Quarterly Progress Report 8/20/03 – 12/01/03, Phillip W. Patton, Mark Rudin Dec 2003

Development Of Dose Conversion Coefficients For Radionuclides Produced In Spallation Neutron Sources: Quarterly Progress Report 8/20/03 – 12/01/03, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

A research consortium comprised of representatives from several universities and national laboratories has been established as part of this project to generate internal and external dose conversion coefficients for radionuclides produced in spallation neutron sources. Information obtained from this multi-year study will be used to support the siting and licensing of future accelerator-driven nuclear initiatives within the U.S. Department of Energy complex, including the Spallation Neutron Source (SNS) and Accelerator Production of Tritium (APT) Projects. Determination of these coefficients will also fill data gaps for several hundred radionuclides that exist in Federal Guide Report No. 11 and in Publications ...


Energy Scaling Law For Buildings, David W. Hafemeister Dec 2003

Energy Scaling Law For Buildings, David W. Hafemeister

Physics

This paper is an ode to my friend Hendrik. We collaborated on hyperfine interactions from 1962 to 1984, when he was colleague and friend. Since then I have been working on the Physics of Societal Issues (Springer Verlag, 2003). The paper below models energy use in buildings, which could save considerable energy with well-designed buildings.


Measurement Of Conductivity And Charge Storage In Insulators Related To Spacecraft Charging, A Robb Frederickson, Jr Dennison Dec 2003

Measurement Of Conductivity And Charge Storage In Insulators Related To Spacecraft Charging, A Robb Frederickson, Jr Dennison

Journal Articles

Improved experimental methods are discussed for laboratory measurement of conductivity and electric field in insulating spacecraft material intended for space radiation and plasma environments. These measurement techniques investigate the following features: 1) Measurements of conductivity are up to four orders of magnitude smaller than those determined by existing standard methods. 2) Conductivity is altered as radiation accumulates and trapping states fill with electrons. 3) With intense keV electron irradiation, electrons are continually emitted for hours from the irradiated surface after the irradiation ceases. 4) Charging induced by electron irradiation is strongly modified by the electron-hole pairs that the irradiation generates ...


Lamb Shift Of Laser-Dressed Atomic States, Ulrich D. Jentschura, Jorg Evers, Martin K. Haas, Christoph H. Keitel Dec 2003

Lamb Shift Of Laser-Dressed Atomic States, Ulrich D. Jentschura, Jorg Evers, Martin K. Haas, Christoph H. Keitel

Physics Faculty Research & Creative Works

We discuss radiative corrections to an atomic two-level system subject to an intense driving laser field. It is shown that the Lamb shift of the laser-dressed states, which are the natural state basis of the combined atom-laser system, cannot be explained in terms of the Lamb shift received by the atomic bare states which is usually observed in spectroscopic experiments. In the final part, we propose an experimental scheme to measure these corrections based on the incoherent resonance fluorescence spectrum of the driven atom.


Modelling Growth And Testing Of Multilayer Cavity Structures Incorporating Birefringent Materials, Nour-Eddine El Khachia Dec 2003

Modelling Growth And Testing Of Multilayer Cavity Structures Incorporating Birefringent Materials, Nour-Eddine El Khachia

Masters

A simple one-dimensional photonic bandgap structure, which is also known as a Fabry-Perot Microcavity (FPM) structure was studied theoretically and experimentally. In particular this project addressed introducing an optically birefringent material in the cavity. This FPM consists of two grown regular Distributed Bragg Reflector (DBR) mirrors that can be put together as a sandwich with a space between them, which will lead to the creation of the desired cavity. Each mirror, or one-dimensional dielectric stack structure, was grown using the Vacuum Evaporation Technique and consists of multiple layers of alternating high-and low-refractive index dielectric materials arranged periodically. The project covers ...


Measurement Of Conductivity And Charge Storage In Insulators Related To Spacecraft Charging, A. R. Frederickson, Jr Dennison Dec 2003

Measurement Of Conductivity And Charge Storage In Insulators Related To Spacecraft Charging, A. R. Frederickson, Jr Dennison

All Physics Faculty Publications

Improved experimental methods are discussed for laboratory measurement of conductivity and electric field in insulating spacecraft material intended for space radiation and plasma environments. These measurement techniques investigate the following features: 1) measurements of conductivity are up to four orders of magnitude smaller than those determined by existing standard methods. 2) Conductivity is altered as radiation accumulates and trapping states fill with electrons. 3) With intense kiloelectronvolt electron irradiation, electrons are continually emitted for hours from the irradiated surface after the irradiation ceases. 4) Charging induced by electron irradiation is strongly modified by the electron-hole pairs that the irradiation generates ...


Probing Scattering Wave Functions Close To The Nucleus, Don H. Madison, Daniel Fischer, Matthew S. Foster, Michael Schulz, Robert Moshammer, Stephenie J. Jones, Joachim Hermann Ullrich Dec 2003

Probing Scattering Wave Functions Close To The Nucleus, Don H. Madison, Daniel Fischer, Matthew S. Foster, Michael Schulz, Robert Moshammer, Stephenie J. Jones, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

Recently, three-dimensional imaging of the ejected electrons following 100  MeV/amu C6+ single ionization of helium led to the observation of a new structure not predicted by theory [M. Schulz et al., Nature (London) 422, 48 (2003)]. Instead of the usual “recoil lobe” centered on the momentum-transfer axis, a ring-shaped structure centered on the beam axis was observed. New measurements at 2  MeV/amu exhibit a similar structure, which is now predicted by theory. We argue that the same theory failed at 100  MeV/amu because the faster projectiles probe distances much closer to the nucleus, where our multiple-scattering ...


Charge Transfer In Slow Collisions Of C⁴⁺ With H Below 1 Kev/Amu, Chen-Nan Liu, Anh-Thu Le, C. D. Lin Dec 2003

Charge Transfer In Slow Collisions Of C⁴⁺ With H Below 1 Kev/Amu, Chen-Nan Liu, Anh-Thu Le, C. D. Lin

Physics Faculty Research & Creative Works

We reexamined charge-transfer cross sections for C⁴⁺ + H collisions for energies from 1 meV/amu to 1 keV/amu using the recently developed hyperspherical close-coupling method. Our results agree with several previous theoretical calculations using molecular-orbital expansion. However, these converged theoretical predictions do not agree with total cross sections from the merged-beam experiments.


Objectivity, Information, And Maxwell's Demon, Steven Weinstein Dec 2003

Objectivity, Information, And Maxwell's Demon, Steven Weinstein

Open Dartmouth: Faculty Open Access Scholarship

This paper examines some common measures of complexity, structure, and information, with an eye toward understanding the extent to which complexity or information‐content may be regarded as objective properties of individual objects. A form of contextual objectivity is proposed which renders the measures objective, and which largely resolves the puzzle of Maxwell's Demon.


“Don’T Tell Me, I’Ll Find Out”: Robert Karplus—A Science Education Pioneer, Robert Fuller Dec 2003

“Don’T Tell Me, I’Ll Find Out”: Robert Karplus—A Science Education Pioneer, Robert Fuller

Robert G. Fuller Publications and Presentations

Robert Karplus (1927–90), who began his career as a brilliant theoretical physicist, switched to science education in the early 1960s. He made many substantial contributions to this field in addition to developing a complete K–6 hands-on science curriculum. Karplus provided his curriculum with a sound epistemological foundation, based on the work of Piaget. He developed an effective classroom teaching strategy, the learning cycle. He and his team used a scientific approach to curriculum development. They focused on teacher development. Karplus was committed to science for ALL students. Through science activities he sought to share the joy of discovery ...


Spatial Frequency Response Of Acrylamide Based Holographic Photopolymer, Raghavendra Jallapuram, Izabela Naydenova, Vincent Toal, Suzanne Martin, Robert Howard Dec 2003

Spatial Frequency Response Of Acrylamide Based Holographic Photopolymer, Raghavendra Jallapuram, Izabela Naydenova, Vincent Toal, Suzanne Martin, Robert Howard

Conference Papers

It has been shown that photopolymers are useful in holographic optical elements [1] and holographic interferometry [2]. However, the list of potential applications increases greatly if reflection holography is possible. Reflection holography requires a material that has the potential to record high spatial frequencies. Here we studied the spatial frequency response of an acrylamide based dye sensitized holographic photopolymer. We have investigated the effect of molecular weight of the binder and concentration of crosslinking monomer on diffusion using real time monitoring of the holographic grating formation. The effect of uniform pre-exposure on diffusion was also investigated. We have also demonstrated ...