Dept. of Physics and Astronomy
102 Natural Science Bldg.
University of Louisville
Louisville KY 40292
(502) 852-6790

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Physics & Astronomy Research at the University of Louisville

The Department of Physics & Astronomy has an active research program with a large number of different projects involving its faculty. All our faculty members are research active; many of their research programs are externally funded. A substantial fraction of the faculty are involved in interdisciplinary research with faculty from other departments in the College of Arts & Sciences and from the Speed School of Engineering. Most of the research in the Department falls into these fields:

Astrophysics Atmospheric Atomic
Condensed Matter High Energy

The University of Louisville also maintains a page containing more general information about university research under the auspices of the Executive Vice President for Research.
 

Astrophysics

Faculty and students in the Department of Physics and Astronomy pursue research in extragalactic, galactic, and stellar astrophysics, laboratory astrophysics, and instrumentation development. Areas of observational research include the use of quasar absorption line systems as tracers of large scale structure, the large-scale distribution of galaxies in large quasar groups, extended emission regions around proto-galaxies and the evolution of the elements in the Universe since the Big Bang. The composition and structure of the interstellar medium in the Milky Way as well as external galaxies are studied using multi-wavelength approaches from the X-rays to the radio.Multi-wavelength imaging and spectroscopic studies of proto-planetary disks are being made to determine the nature and evolution of planetary formation around other stars. Laboratory and theoretical physics are being applied to reveal the structure and evolution of brown dwarf stars. Finally, advanced technologies in optical and computer sciences are opening windows in the near infrared for high dynamic range adaptive time-resolved imaging.

We utilize both ground and space-based facilities such as the telescopes at Kitt Peak National Observatory, Apache Point Observatory, the Hubble Space Telescope, and the Gemini Observatories to pursue both galactic and extragalactic observational studies. The department also operates Moore Observatory, near Louisville, Kentucky, and in collaboration with the University of Southern Queensland, Mt. Kent Observatory near Toowoomba, Australia. A 0.6-meter technically advanced research telescope at Moore Observatory, is used for a training and research programs in instrumentation and stellar astrophysics. The observatories are home to a pair of remotely operable robotic 0.5-meter telescopes that provide nearly continuous coverage of the entire sky and permit a rapid response to transient events such as gamma ray bursts, supernovae, and exo-planet transits. Through Internet2, these robotic telescopes deliver hands-on astronomy education to undergraduate students on campus, and to schools throughout the state.

Research on the dynamics and thermodynamics of planetary atmospheres is carried out using the EPIC Atmospheric model, funded by NASA and NSF, which is a general circulation model designed for planetary applications. EPIC stands for "Explicit Planetary Isentropic Coordinate" and is the leading model for the atmospheres of the gas giants Jupiter, Saturn, Uranus, and Neptune. The model can also be used to simulate terrestial-class atmospheres. This work is carried out at the Comparitive Planetology Laboratory.

Faculty

Representative Publications

  • Study of the K-H_2 quasi-molecular line satellite in the potassium resonance line, N. F. Allard, F. Spiegelman, and J. F. Kielkopf, Astronomy and Astrophysics, 465, 1085-1091 (2007).
  • Impact broadening of alkali lines in brown dwarfs, N. F. Allard, J. F. Kielkopf, and F. Allard, European Physical Journal D -- Atomic, Molecular and Optical Physics, 44, 507-514 (2007).
  • Optical Absorption Line Observations of Small Scale Interstellar Structure, J. T. Lauroesch, Astronomical Society of the Pacific Conference Series, 365, 40 (2007, ed. M. Haverkorn and W. M. Goss)
  • New abundance determinations in z < 1.5 QSO absorbers: seven sub-DLAs and one DLA, J. D. Meiring, J. T. Lauroesch, V. P. Kulkarni, C. P roux, P. Khare, D. G. York, and A. P. S. Crotts, Monthly Notices of the Royal Astronomical Society, 376, 557 (2007)
  • A Link Between Gas-Rich Protoplanetary Disks and Gas-Poor Debris Disks, Collins, K.A., Grady, C.A., Hamaguchi, K., Wisniewski, J.P., Brittain, S., Sitko, M., Carpenter, W.J., Williams, J.P., Matthews, G.S., Williger, G.M., van Boekel, R., Carmona, A., van den Ancker, M.E., Meeus, G., Chen, X.P., Petre, R., Woodgate, B.E., Henning, Th. ApJ, 697, 557 (2009).
  • The Connection between a Lyman Limit System, a very strong OVI Absorber, and Galaxies at z ~ 0.203, Lehner, N., Prochaska, J.X., Kobulnicky, H.A., Cooksey, K.L., Howk, J.C., Williger, G.M., Cales, S.L., ApJ, 694, 734 (2009).


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Atmospheric Physics

Atmospheric physics research at the University of Louisville specializes in planetary atmospheres with a focus on atmospheric dynamics and thermodynamics. The EPIC atmospheric model, a general circulation model (GCM) designed for plantery applications, was developed here and funded by NASA and NSF. EPIC stands for "Explicit Planetary Isentropic Coordinate" and is the leading model for the atmospheres of the gas giants Jupiter, Saturn, Uranus, and Neptune. The model can also be applied to terrestial class atmospheres including Venus, Earth, Mars, and Titan (a large moon of Saturn with a substantial atmosphere). Current topics of research include Jupiter's Great Red Spot, thunderstorms on Jupiter and Saturn, jet-stream stability, Venus and Titan spinup and superrotation, and the dynamics of vortices and clouds on Uranus and Neptune. (Dowling)

Active research in atmospheric turbulence also takes place in the department. The stable atmospheric boundary-layer exhibits significant complexity due to the interactions between several phenomena over multiple scales .Using the National Taiwan University-Purdue University Nonhydrostatic model with higher-order turbulence closure schemes, simulations are probing the role of internal gravity waves as an excitation mechanism for isolated layers of turbulent mixing. These gravity waves may be generated from shear layers inside or outside the boundary-layer or from topography. The goal is to shed light on the poorly-understood energetics surrounding the formation of turbulent structures in stable environments. (MacCall)

Faculty

Representative Publications

  • The emergence of multiple robust zonal jets from freely evolving, three-dimensional stratified geostrophic turbulence with applications to Jupiter , K.M. Sayanagi, A.P. Showman, T.E.Dowling, J. Atmos. Sci. 65, 3947-3962 (2008).
  • Addition of water and ammonia cloud microphysics to the EPIC model, CsJ Palotai, T.E.Dowling, Icarus 194, 303-326 (2007), doi: 10.1016/j.icarus.2007.10.025.
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Atomic, Molecular and Optical Physics

Atomic, Molecular and Optical Physics research in the department includes theoretical work on small molecules focusing on those of astrophysical interest, laboratory astrophysics investigating radiative processes in stellar atmospheres, and applied optical physics, providing advanced technology and analysis to infrared imaging. Note that other research areas in the department, notably condensed matter physics and astrophysics, are deeply connected with atomic, molecular and optical physics.

In the theoretical effort, mathematical techniques are being developed which make it possible for the first time to obtain a very accurate representation of the excited states of diatomic molecules. These methods enable us to study very precisely the energy of small molecules as a function of interatomic distance and to study dynamical processes such as photoionization and molecular dissociation. (Morrison). The theory of radiative collisions is being applied to the atmospheres of cool dense stars. (Kielkopf).

Laboratory experimental work is directed toward precision measurements that test the accuracy of theoretical calculations of interatomic potentials, radiative transition rates, and spectral line shapes under well defined conditions. The laboratory facility includes extremely high resolution optical and vacuum ultraviolet spectrometers, as well as laser-plasma sources. The laboratory supports an intensive collaborative program with research groups in Electrical and Computer Engineering to develop near-infrared imaging devices with on-pixel processing. These devices have applications in adaptive optics for astronomy, remote sensing and surveillance (Kielkopf.)

Faculty

Representative Publications

  • Self-Broadening of the Hydrogren Balmer-alpha Line, N.F. Allard, J.F. Kielkopf, R. Cayrel, and C. van't Veer-Menneret, Astron. Astrophysics, 480, 581-587 (2008).
  • Numerical Methods for Solving the Hartree-Fock Equations of Diatomic Molecules, J. Morrison, S. Boyd, L. Marsano, B. Bialecki, T. Ericsson, and J.P. Santos, accepted for publication Computer Physics Communications.

 

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Condensed Matter Physics

The experimental and theoretical efforts in condensed matter physics at the University of Louisville deal with a wide range of solid state phenomena. Active research is presently being carried out on catalytic materials, ferroelectric crystals, mixed crystals, polycrystalline and amorphous solids, and a variety of organic compounds and super-conductors. Many of these projects are related to important practical applications as well as more fundamental questions concerning the properties of matter.

Our solid state experimental group uses the techniques of nuclear magnetic resonance (NMR), and positron annihilation studies (PAS). In the NMR work, nuclei having spin-dipole and quadruple moments are used to probe the electric and magnetic fields of solids. The electric field at the site of the nucleus is especially sensitive to the properties of the valence and bonding electrons. So these experiments produce results of both physical and chemical importance. The NMR research has been directed principally to understanding in detail how the lineshapes obtained by the absorption and dispersion modes are related to the electric quadrupole and magnetic dipole interactions for polycrystalline and amorphous solids. (France)

The molecular dynamics/transport, phase behavior, as well as the emerging novel physical phenomena and applications under nanoconfinement are studied in a variety of novel materials. In parallel, we develop NMR and MRI methods such as novel nuclear spin -lattice relaxation filter, fast imaging sequences, and simultaneous multi-dimensional diffusometry. (Tang ).

In a solid medium, positrons are thermalized quickly and annihilate with electrons in the material. For this reason, PAS has been employed as a micro-probe for studying electronic structures of a great variety of substances. In our department, this technique has been applied to investigate electronic properties of superconductors, catalysts and some organic polymers. The positron laboratory is equipped for performing angular correlation, Doppler broadening and positron lifetime measurements. Studies of high Tc superconductors are also in progress with techniques including I-V characteristics, thermoelectric power, magnetic susceptibility and tunnelling microscope (Huang).

The Condensed Matter Theory Group is engaged in forefront research in nanoscience that involves predicting the structures and properties of nanoscale systems as well as novel phenomena, using state-of-the-art quantum mechanics based molecular dynamics simulations. The current research of the group is focused on studies involving structural, electronic, vibrational and transport properties of carbon-based and silicon-based nanoclusters, nanowires and surfaces. (Jayanthi, Liu, Wu, Yu) .

Due to their potential technological applications, there has been an increased interest in molecular films. Applications in optical and electronic devices, electroanalytical chemistry, and biological interfaces illustrate the intense attention on organic and biological thin films in the monolayer and submonolayer regimes. To fully exploit the technological possibilities offered by molecular films, a number of scientific problems need to be addressed. Among them is the relationship between structure in molecular assemblies and the corresponding chemical and biological properties. Investigation in molecular films requires experimental tools able to perform in-situ non-destructive analysis with the high sensitivity needed for submonolayer detection. Our research focus on novel analytical tools based on integrated optics and surface waves for research in biomolecular films and interface phenomena, on the spectroscopic investigation of the physical/chemical properties of biomolecular films, and on the integration of nano-structured photonic devices with molecular assemblies for selective and sensitive transduction in chemical and biological materials. ( Mendes)

Other experimental studies involve synthesis, characterization, device fabrication, and property measurements of various nanostructures including carbon nanotubes, semiconducting nanowires, and 3-D colloidal crystals (opals). Pulsed Laser Vaporization, Chemical Vapor Deposition (including RF plasma, Hot filament, Vapor transport reaction), and template directed growth are used for nanowire synthesis. HRSEM, HRTEM, Micro Raman, XRD, EDX are routinely used for material characterization. E-beam lithography, photolithography, wire bonding are used for device fabrication. Electrical transport properties are studied by measuring electrical resistivity, thermal conductivity, and thermo electric power in the temperature range 10-500 K and magnetic fields up to 3 Tesla (Sumanasekera).

Faculty

Representative Publications

  • Energetics, Relative Stabilities and Size-Dependent Properties of Nanosized Carbon Clusters of Different Families: Fullerenes, Bucky-Diamonds, Icosahedral, and Bulk-Truncated Structures, M. Yu, I. CHaudhuri, C. Leahy, S.Y. Wu, and C.S. Jayanthi, Journal of Chemical Physics 130, 184708 (2009).
  • The Self-Consistent and Environment-Dependent Hamiltonian and its Application to Carbon Nanoparticles, W.Q. Tian, M. Yu, C. Leahy, C.S. Jayanthi, and S.Y. Wu, J. Computational and Theoretical Nanoscience, Vol. 6, 1-7, (2008).
  • Stability and Mechanical Properties of Silicon Nanowires, Shudun Liu, C.S. Jayanthi, Zhenyu Zhang, and S.Y. Wu, Journal of Computational and Theoretical Nanoscience, Special Issue on Nanomorphology, Vol. 4, 275 (2007).
  • Confined phonons in Si nanowires, K. W. Adu , H. R. Gutierrez , U. J. Kim , G. U. Sumanasekera , P. C. Eklund, American Chemical Society, 49(2), 885-886 (2004).
  • A 13C NMR Study of the Molecular Dynamics and Phase Transition of Confined Benzene inside Titanate Nanotubes-Y¡, Tang, X.P., Wang, J.C., Cary, L., Kleinhammes, Y. Wu, Journal of American Chemical Society 127, 9255 (2005).
  • Synthesis of Gold Nanorod/single-wall carbon Nanotube Heterojunctions Directly on Surfaces, A.J, Mieszwska, , R. Jalilian, G. Sumanasekera, G., Zamborini, Journal of the American Chemical Society, 127 (31): 10822 (2005).
  • Planar Integrated Optical Waveguide Spectroscopy, Bradshaw, J. T.; Mendes, S. B.; Saavedra, S. S. Analytical Chemistry (2005) 77(1), 28A-36A.
  • Order Parameters and Orientation Distributions of Solution Adsorbed and Microcontact Printed Cytochrome c Protein Films on Glass and ITO and their Relationship to the Rate of Electron Transfer, Runge, A. F; Mendes, S. B.; Saavedra, S. S. Journal of Physical Chemistry B (2006) 110(13), 6732- 6739.

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High Energy Physics

The High Energy Physics group at the University of Louisville is concerned with fundamental questions about the basic structure of matter and its interactions. We ask why the visible universe seems to be dominated by ordinary matter (where has the anti-matter gone?), why are the masses of the particles in nature what they are, and how do the interactions among these particles help shape the universe? In particular, we study the production of the relatively heavy proton and neutron and related heavy particles known collectively as baryons. We hope to understand the surprising 'abundance' of these particles in matter.

We are members of the BaBar Collaboration and the ATLAS Collaboration. The BaBar detector collected data from 1999 to 2008 in electron-positron collisions at the SLAC National Accelerator Lab in California. ATLAS began taking data in late 2009 with proton-proton collisions at the Large Hadron Collider (LHC) of the European Organization for Nuclear Research (CERN - which stands for the French "Conseil Europeen de Recherche Nucleaire"). BaBar has produced copious high-quality data that we will continue to analyse for many years. ATLAS is just beginning to produce high-quality data for analysis and discovery over the coming decades.

Babar is a large, general-purpose electron-positron collider detector operating at center of mass energies near 10 GeV. The experiment ran in the PEP-II storage rings at SLAC in "B-Factory" mode, meaning that it was tuned for optimal production of the B meson, a particle whose decays provide an excellent glimpse at matter-antimatter asymmetry. Currently, the University of Louisville group is investigating probes of QCD in quark and gluon jets, studying inclusive hadron production, and searching for rare CP-violating decays of the B-meson to final states with baryons. This work involves extensive software development. The group has been steadily involved in software development and administration on BaBar since 1996. (Brown, Davis).

On ATLAS, we are assisting with simulations of radiation backgrounds that affect the detector. In data, we will be searching for as-yet unseen triply heavy baryon states. This will help us fill in our knowledge of the possible baryonic particle states, but will also aid in understanding the production mechanisms of baryons. (Brown)


Faculty

Representative Publications

  • Searches for B Meson Decays to φφ, φρ, φf0(980) and f0(980)f0(980) Final States, B. Aubert, D. N. Brown, C. L. Davis et al. (BABAR Collaboration), Phys. Rev. Lett. 101, 201801 (2008)
  • Measurement of the Branching Fractions of Bbar → D**lνl Decays in Events Tagged by a Fully Reconstructed B Meson, B. Aubert, D. N. Brown, C. L. Davis et al. (BABAR Collaboration), Phys. Rev. Lett. 101, 261802 (2008)
  • Measurements of B(Bbar0 → Λc+ pbar and B(B- → Λc+ pbar π-) and studies of Λc+π- resonances, B. Aubert, D. N. Brown, C. L. Davis et al. (BABAR Collaboration), Phys. Rev. D 78, 112003 (2008)


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