# Physics Colloquium Schedule

## Department of Physics University of South Alabama

DATE
 SPEAKER
Thursday

October 23, 2014

4:00 PM

ILB Room 250

### The Role of Quantum Mechanics in the Process of Materials Design

The laws of quantum mechanics form the basis for our understanding of the elements in the periodic table and their interactions in compounds. Materials science in the 20th century can be broadly characterized as evaluating the properties of particular materials in terms of these fundamental laws. With our increasing understanding of structure/property relationships the focus of materials science continues to shift toward rational materials design. However, while the fundamental physical laws of electrons in materials are well established, the a priori identification of candidate materials with particular targeted properties remains a significant challenge. I will discuss how our current understanding of the periodic table can inform our search of promising material sets for particular applications. Advanced computational methodologies are an integral part of this effort: They allow the evaluation of the effects of composition and crystal structure on electronic and magnetic properties before materials synthesis and provide invaluable guidance for materials selection. During the presentation I will address how our first-principle computations inform the design of novel 3d and 5d transition metal compounds with applications in spintronics and related areas.

Tuesday

October 14, 2014

4:00 PM

ILB Room 250

### Probing the Frontiers of Physics Using Rare Particle Decays

The absence of any signature for new physics beyond the standard model at the Large Hadron Collider has left the field of elementary particle physics in a quandary. We know there is new physics out there: where best to look for it? I will show how sensitive searches beyond the frontiers of particle physics will done in the next decade at Fermilab using rare particle decays to explore mass scales unobtainable by any conceivable accelerator.

Thursday

September 25, 2014

3:00 PM

ILB Room 250

### Simulation Technique for Modeling Adsorption and Reactions at Interfaces

As the study of chemical processes, biological phenomena, and material science has reached the nanometer length scale, the physics of an interface has become an increasingly important topic. While experimental investigations are indispensable, simulations provide a complementary approach to study these systems. We are currently using molecular simulation methods and electronic structure calculations to investigate adsorption and reactions on surfaces and at interfaces, including: (a) Reaction thermodynamics at interfaces: Reactive Monte Carlo (RxMC) simulations are used to predict the effect of a vapor-liquid interface on the thermodynamics of a chemical reaction. Also, we highlight the replica-exchange version of the RxMC technique that can accelerate these simulations in challenging situations. (b) Development of improved models for adsorption: A combination of molecular dynamics and electronic structure calculations are used to develop realistic interaction potentials for adsorption simulations. In particular, we have developed interaction potentials for carbon-platinum and for adsorption on MoS2 surfaces. (c) Molecular-level design for industrial gas separation: Imidazole-based solvents possess many of the tunable solvation properties and low vapor pressures associated with ionic liquids, but imidazoles have significantly lower viscosity, which is beneficial for industrial applications. In order to accelerate development of these solvents, we are developing descriptor-based approaches for predicting their thermochemical properties.

Thursday

April 17, 2014

3:00 PM

ILB Room 250

### Solar Flares

Because the Earth resides in the atmosphere of our nearest stellar neighbor, events occurring on the Sun's surface directly affect us by interfering with satellite operations and communications, astronaut safety, and, in extreme circumstances, power grid stability. Solar flares, the most energetic events in our solar system, are a substantial source of hazardous space weather affecting our increasingly technology-dependent society. While flares have been observed using ground-based telescopes for over 150 years, modern space-bourne observatories have provided nearly continuous multi-wavelength flare coverage that cannot be obtained from the ground. We can now probe the origins and evolution of flares by tracking particle acceleration, changes in ionized plasma, and the reorganization of magnetic fields. I will walk through our current understanding of why flares occur and how they affect the Earth and also show several examples of these fantastic explosions.

References:
• Savage et al., "Low-altitude Reconnection Inflow-Outflow Observations during a 2010 November 3 Solar Eruption" 2012, ApJ, 754, 13S http://adsabs.harvard.edu/abs/2012ApJ...754...13S
• Savage, McKenzie, and Reeves, "Re-interpretation of Supra-arcade Downflows in Solar Flares" 2012, ApJL, 747, 40S http://adsabs.harvard.edu/abs/2012ApJ...747L..40S
Thursday

September 26, 2013

3:00 PM

ILB Room 250

### 3-D Global Simulation of Plasma Kinetic Processes in the Earth's Magnetosphese

Dynamics of the Earth's magnetosphere is driven by the solar wind, i.e., streams of charged particles from the Sun that consist mainly of protons and electrons. Plasma and energy transport at the magnetopause, the boundary between the solar wind and the magnetosphere, depends highly on the direction of the interplanetary magnetic field (IMF). When the IMF points northward, the magnetopause is magnetically 'closed' on the dayside, whereas when the IMF points southward, the magnetopause is 'open' to the solar wind due to a fundamental process called magnetic reconnection. In this talk, we investigate the transport at the dayside magnetopause using a powerful computation model, the 3-D global hybrid simulation model, which is a self-consistent plasma kinetic model that treats protons as fully kinetic particles and electrons (mass is 1836 times lighter) as a fluid and covers the broad plasma regions from the solar wind to the magnetosphere. Direct plasma transport due to magnetic reconnection under a southward IMF and the diffusive transport due to plasma wave-particle interaction under a northward IMF will be addressed. In addition, the wave particle-interaction at the bow shock in front of the magnetopause causes the acceleration of the solar wind particles, which can then be transmitted into the polar region of the magnetosphere and lead to the observed cusp energetic ions.

References:
• Y. Lin and X.Y. Wang, "Three-Dimensional Global Hybrid Simulation of Dayside Dynamics Associated with the Quasi-Parallel Bow Shock", Journal of Geophysical Research, 110, A12216, doi: 10.1029/2005JA011243, 2005.
Thursday

March 7, 2013

3:00-4:00 P.M.

ILB Room 250

### Supersymmetry and the Higgs Boson at the LHC

The year 2012 may be forever remembered in physics as the year in which the long-hunted Higgs boson was finally cornered. It was also one more year in which supersymmetry, the long-sought guardian of the Higgs, was not found. Has supersymmetry simply eluded us? Is it waiting for the next, higher energy phase of the LHC program? I will examine the coupled motivations for the Higgs boson and for supersymmetry, and consider whether the current data is pointing to weak-scale supersymmetry, or can be used to rule the theory out entirely.

References:
• K. Dienes and C. Kolda, Twenty Open Questions and a Postscript: Supersymmetry enters the era of the LHC. Published in Perspectives on Supersymmetry II, ed. G. Kane, 2010.
Thursday

November 1, 2012

3:00 PM

ILB Room 250

### Surface Plasmon Enhanced Polymer Photodetecting/Photovoltaic Devices

Although metals are shiny materials that highly reflect visible light, it is well known that light transmission through metals increases beyond the plasma frequency. Nanoplasmonics is a relatively new field of technology that studies surface plasmons, the collective oscillations of free electrons on the interface between metal clusters and a dielectric. When the metal clusters interact with light, the surface plasmon resonance can be observed. This surface plasmon resonance can improve light absorption, charge separation or charge collection in devices and finds its application in biomedical engineering, optoelectronic devices, waveguides, and Raman spectroscopy. In this colloquium we will focus how surface plasmons can improve efficiency in polymer bulk heterojunction photodetecting and photovoltaic devices

References:
• D. A. Genov, A. K. Sarychev, and V. M. Shalaev, Surface plasmon excitation and correlation-induced localization-delocalization transition in semicontinuous metal films, Phys. Rev. B 72, pp. 113102-1-4, 2005.
• H. A. Atwater and A. Polman, "Plasmonics for improved photovoltaic device," Nature Materials, vol. 9, pp.205-213, 2010.

Thursday

September 27, 2012

7:30-8:30 p.m.

ILB 140

### The Search for Habitable Worlds

Humans have undoubtedly asked "Are We Alone?" for millennia, but ours is the generation in which we take the first step towards an answer by asking "Do Habitable Planets Exist?" I will begin with our primitive definition of habitable, using the case studies from our solar system: Venus, Earth, Mars - and Jupiter's icy moon Europa. What planetary properties ultimately control a planet's habitability? Then I will describe the search for extrasolar planets, both methods and results. I will concentrate on the Kepler mission which is closing in on its ambitious goal of "Earth-sized planets on Earth-like orbits around Sun-like stars". With an average discovery rate of several planets per day, it may just be a matter of time before Kepler finds one. What then??

References:

Thursday

September 27, 2012

3:00-4:00 p.m.

ILB 250

### Exploring Mars: Curiosity, MAVEN, INSIGHT and Beyond

NASA's Curiosity rover became a household name when it landed in August, but it's only one of an impressive suite of missions to reveal the secrets of Mars' surface, atmosphere and deep interior. The talk will begin with a review of the latest news from Curiosity, and its role in the search for evidence of a warmer, wetter climate in the past. Then I will describe the upcoming MAVEN mission, launching in 2014. MAVEN is an orbiter designed to study the upper atmosphere and test the hypothesis that most of Mars' atmosphere was lost to space. I will emphasize the role of the Imaging UV Spectrograph, undergoing final tests now at the Laboratory for Atmospheric & Space Physics. One of the instrument's key capabilities is the challenging measurement of the deuter1ium-to-hydrogen ratio, an critical test of atmospheric escape. I will follow with a brief preview of NASA's just-announced INSIGHT mission, carrying a seismometer and drill to probe Mars' interior. I will end with a short discussion of the long-term possibilities of a Mars Sample Return mission and human exploration of Mars.

Reference:
Thursday

March 29, 2012

3:30 - 4:30 P.M.

ILB Room 250

### Big Bang in a Small Space: Relativistic Heavy Ion Physics

About 10 microseconds after the big bang, the universe was too hot and dense for quarks to bind to form protons, neutrons and other hadrons. Instead, it may have existed in a state called the quark-gluon plasma, in which quarks and the gluons that carry the strong force roamed unconfined. Scientists may have recently produced this state in the laboratory using large particle accelerators to collide heavy ions at enormous energies, producing matter a billion times hotter than the sun. I will discuss experimental approaches to the production, detection, and characterization of this novel state of matter as well as the latest results from the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN.

References:
• Dependence on pseudorapidity and on centrality of charged hadron production in PbPb collisions at sqrt(s_NN) = 2.76 TeV/CMS Collaboration J. High Energy Phys. 08 (2011) 141

Thursday

February 16, 2012

3:30-4:30 P.M.

ILB 250

### New Bound States in Quantum Chromodynamics

Quantum Chromodynamics (QCD) is the theory that describes how quarks and gluons bind to form protons, neutrons, mesons, and their partner particles. But after decades of effort, we still do not know exactly *how* this happens. In particular, we have a theory, but have not been able to use that theory to make reliable predictions about excited bound states, although various models and numerical simulations exist. Recently, new and totally unexpected particles were found at so-called B-factories, and confirmed at other facilities. These new particles appear to be bound states of QCD of a type that have never been seen before. We hope that by analyzing their behavior we can obtain clues about how they are formed. I will discuss the properties of these new particles and what insights they provide about QCD.

References:
• N. Brambilla, et al. "Heavy quarkonium: progress, puzzles, and opportunities," Eur.Phys.J. C71 (2011) 1534, arXiv: 10105827 (hep-ph), section 2.3.
Thursday

October 13, 2011

3:30 - 4:30 PM

ILB Room 250

### Tick, Tock: Simulating a Molecular Clock

In this talk I will briefly review the nature and scope of various types of information being acquired at the molecular level from cells and mention various challenges we face in integrating this type of data into the creation of mathematical models of various biophysical processes. One of the simplest biophysical systems which displays interesting dynamics is the circadian (~24hr) clock from cyanobacteria. It is the first and only known molecular circadian clock which functions outside a cell (in a test tube) and consists of just three distinct proteins. I will give an experimental theoretical overview of this in vitro clock and describe recent attempts to extend the in vitro models to include transcription and translation processes in cells. Recent direct numerical simulations of the clock using a stochastic matrix model with rates constrained by experiment indicate specific molecular mechanisms necessary for maintaining synchrony; similar mechanisms may also be operative in clocks from higher organisms or more generally in other intracellular processes where population synchronization is needed for temporal precision.

References:
• Nakajima M, Imai K, Ito H, Nishiwaki T, Murayama Y, et al. (2005) Reconstitution of circadian oscillation of cyanobacterial KaiC phosphorylation in vitro. Science 308: 414-415.
Thursday

September 29, 2011

3:30 - 4:30 PM

ILB Room 250

### To be or not to be: Superconductivity and Thermoelectrics for Green Energy Application

The phenomena of superconductivity and thermoelectrics are extremely attractive for green energy applications, because they are environmentally benign. However, adequate materials with high efficiency and low cost are yet to be discovered. In my talk, I will discuss the advances and challenges in these two fields.

References:
• F. Hunte et al "Two-band superconductivity in LaFeAsO(0.89)F(0.11) at very high magnetic fields" Nature Letters Vol 453| 12 June 2008
Thursday

September 15, 2011

3:30 - 4:30 P.M.

ILB Room 250

### Organic Semiconductors: Bright Future for Old Materials

Organic molecules such as tetracene crystallize into solids that can be semiconductors, metals, or even superconductors. Although they were rst developed over half a century ago, it is only fairly recently that the considerable promise that organic semiconductors hold as materials for electronics, display technologies, and solar cells has begun to be realized. Lightweight, exible, and inexpensive, these materials oer an attractive balance between cost and performance, complemented by versatility and functionality accomplished by means of molecular design. I will review the physics of organic semiconductors and describe how their electronic and optical properties can be utilized in a variety of applications.

References:
• H. Klauk,"Organic thin-film transistors,"Chemical Society Reviews 39, 2643-2666 (2010). DOI: 10.1039/b909902f
Thursday

April 21, 2011

4:00 PM

ILB Room 250

### Totally Out of Equilibrium: Genes, Stocks, and Traffic

Statistical physics forms the traditional foundation for thermodynamics, illustrating how concepts such as entropy and temperature emerge from the statistics of many interacting molecules. This framework has been immensely successful for systems in thermal equilibrium. Yet, many of the most interesting phenomena in nature take place very far from equilibrium - including, for example, living organisms or the earth's ecosystem. In this talk, I will try to give a flavor of the breadth of non-equilibrium phenomena and how to apply lessons learned in physics to much broader, interdisciplinary questions such as the modeling of biological systems, stock indices and traffic jams.

References:
• Statistical Mechanics of Driven Diffusive Systems. B. Schmittmann and R.K.P. Zia, Vol 17 of Phase Transitions and Critical Phenomena, eds. C. Domb and J.L. Lebowitz (Academic Press, N.Y. 1995), 220 pp.
• Towards a model for protein production rates. J.J. Dong, B. Schmittmann, and R.K.P. Zia, Journal of Statistical Physics 128, 21-34 (2007), Special Issue on Biocomplexity VIII: Applications of Methods of Stochastic Systems and Statistical Physics in Biology; q-bio.BM/0602024.
• Lack of consensus in social systems. I. J. Benczik, S. Z. Benczik, B. Schmittmann, and R.K.P. Zia, Europhysics Letters 82, 48006: 1-5 (2008); arXiv:0709.4042

PUBLIC LECTURE
Thursday

April 14, 2011

7:30-8:30 P.M.

Life Sciences Lecture Hall 3

### HOW MANY UNIVERSES?

This lecture will explore the development of our knowledge and understanding of the extent of Universe-in both space and in time. Beginning 100 years ago with the view that the universe contained a single galaxy, a few million visible stars and 9 planets, we will move on to Hubble's discovery of billions of other galaxies and the expansion of the Universe and to current understanding of a Universe comprised of dark matter and dark energy with billions of planets (now only 8 in our solar system!). The lecture will end with speculations about the multiverse and its philosophical implications.

References:
• Frieman, Turner, and Huterer, Annual Reviews of Astronomy and Astrophysics 46, 385 (2008) [arXiv: arXiv:0803.0982]
Thursday

April 14, 2011

3:00 PM

ILB Room 250

### Cosmic Acceleration and Dark Energy

A little over ten years ago two groups studying distant supernovae discovered that the expansion of the Universe is speeding up and not slowing down, and in December 1998 Science Magazine picked Cosmic Acceleration as the Scientific Breakthrough of the year. This remarkable discovery provided the final, missing piece in today's consensus cosmological model as well as posing the most profound mystery in all of science. Two possible explanations for cosmic acceleration are the repulsive gravity of a mysterious and very elastic new form of energy (dark energy'') or new gravitational physics. Ten years after the discovery, the evidence for cosmic acceleration has gotten stronger and the mystery has deepened. In this talk I will review the present status of the mystery of cosmic acceleration.

References:
• Frieman, Turner, and Huterer, Annual Reviews of Astronomy and Astrophysics 46, 385 (2008) [arXiv: arXiv:0803.0982]
Thursday

March 24, 2011

4:00 PM

ILB Room 250

### MAGNETIC RESONANCE IMAGING

A brief overview of the basic phenomena and principles of image acquisition and reconstruction will be presented. We will also present examples of functional Brain Imaging, Magnetic Resonance Angiography (MRA), and Gadolinium Contrast Imaging.

References:
• The Essential Physics of Medical Imaging. Bushberg et al.
• Magnetic Resonance Imaging. S. C. Bushong.
Thursday

October 28, 2010

4:00 - 5:00 P.M.

ILB Room 250

### Strange Beauty and Other Beasts: At and Above the Upsilon(5S) with Belle

The B-factories have successfully exploited the unique advantages of the Upsilon(4S) resonance to study many aspects of the Bd and Bu mesons. The Upsilon(10860) resonance, also known as Upsilon(5S), which is above mass threshold for the Bs and shares many of the same advantages, has been relatively unexplored. The Belle experiment has collected 120 fb-1 at the Upsilon(10860) and 7.9 fb-1 at higher energies, corresponding to more than 10 million Bs events. Recent results based on ~20% of these data will be presented, and prospects for future possibilities will be discussed.

Reference:
• K.Kinoshita. Strange Beauty and Other Beasts from Upsilon(5S) at Belle http://arxiv.org/abs/1005.3893.
Friday

October 8, 2010

3:45 - 4:45 P.M.

ILB Room 250

### Observations and Double Star Measurements with a 17th Century Telescope - Surprising Results!

As part of the evaluation of my long-focal, non-achromatic refractor of the type developed during the first century, i.e., the 17th century, of optical astronomy, I have observed 175 double and multiple stars. About a year ago, after having observed most of these binary stars visually, I decided to see if it would be possible to measure their position angles and separations. Thus, I built a micrometer and began a program to determine if - and how accurately - I could measure the characteristics of these binaries. To my great surprise, the average error of the measured position angles is only 2 degrees and that of the separations is only 1 arc-second - values that are almost a good as modern measurements. These results further indicate that these very early and relatively primitive telescopes were much better that modern astronomical historians believe.

References:
• The Performance Characteristics of 17th Century Long-Focus, Non-Achromatic Refractors, Journal of the Antique Telescope Society, Issue No. 31 - Winter 2010, pp 3-17.

PUBLIC LECTURE

Thursday

April 1, 2010

7:00-8:30 P.M.

ILB 140

### Astrobiology of the Solar System: Looking for Life in All the Right Places

As soon as the Copernican revolution made humanity aware that the Earth is one planet among many, speculation began about the possibility that other planets might be inhabited. The main focus of interest always has been Mars, with the most Earth-like surface conditions of any planet. Robot orbiters and rovers have recently found clear evidence that Mars was once wetter and warmer than at present. In addition, Viking Mars lander soil test results from the 1970s indicated possible biological activity, and some investigators believe Mars rock ALH84001 contains fossil microbes plus their metabolic products. Beyond Mars, there is evidence for liquid water under ice crusts on Jupiter's moons Europa and Ganymede and Saturn's moon Enceladus, as well as abundant organic compounds in the atmosphere and on the surface of Saturn's moon Titan. Could any of these worlds harbor Earth-like, water-and-carbon-based life? Astrobiology research and planetary exploration may reveal answers within just a few decades

References:
• "Horizons" 11th edition, 2009, Seeds and Backman, Chapter 20
• "Foundations of Astronomy", 11th edition, 2010, Seeds and Backman, Chapter 26
• "Search for Life in the Universe", Goldsmith and Owen, 3rd edition

Thursday

April 1, 2010

4:00-5:00 P.M.

ILB 250

### SOFIA: NASA's Stratospheric Observatory for Infrared Astronomy

The SOFIA observatory, presently undergoing a series of test flights leading to the start of scientific observations in mid-2010, is a 2.5-meter telescope mounted in a heavily modified Boeing 747SP aircraft. History of the project, details of its current status, and SOFIA's scientific promise as the premier world infrared and sub-millimeter observatory for the next 20 years will be presented.

References:
• http://www.sofia.usra.edu/
• http://arxiv.org/abs/0905.4271

Thursday

February 25, 2010

4:00-5:00 P.M.

ILB 250

### Observing the Atmosphere with the University of South Alabama Mesonet

A Mesonet'' is a meteorological term meaning a network of weather stations that are spaced between 1 and 100 km apart. The University of South Alabama has operated its own Mesonet since 2006. The network currently consists of 16 stations and will soon be expanded to 26 stations located in the coastal and near-coastal counties of Mississippi, Alabama, and the Florida Panhandle. The spacing between stations ranges from 5.4 to 55.6 km with an average of about 30 km. Each station observes 14 meteorological parameters every minute. Archived and (near) real-time data are available on our web site (http://chiliweb.southalabama.edu/) for research, teaching, and forecasting purposes. Data uses are not limited to meteorology; a wide range of disciplines use weather data including agricultural interests, hydrologists and civil engineers, biologists and environmentalists, chemical companies, and more. Many interesting weather phenomena and basic physical principles that apply in the atmosphere have been observed during the 3-year existence of the network. In this presentation, the configuration of the weather stations, the data collected, and the data flow will be explained. Several interesting atmospheric phenomena including nocturnal inversions, sea-breezes, and tropical storms will be described with the aid of weather station data.

References:
• Kimball, Sytske K, Madhuri S. Mulekar, Shailer Cummings, Jack Stamates, 2010: The University of South Alabama mesonet and coastal observing system: A technical and statistical overview. Journal of Atmospheric and Oceanic Technology. Conditionally accepted for publication
• Kimball, Sytske K, 2008: Structure and evolution of rainfall in numerically simulated landfalling hurricanes. Monthly Weather Review, 136, 3822 - 3847
• Jeffrey M. Medlin, Sytske K. Kimball, and Keith G. Blackwell, 2007: Radar and rain gauge analysis of the extreme rainfall during Hurricane Danny's (1997) landfall. Monthly Weather Review, 135, 1869 - 1888

Tuesday

November 17, 2009

7:00-8:30 P.M.

HUMB 150

### Listening to the Universe with Gravitational Waves

Gravitational waves are commonly referred as "ripples in the fabric of space-time". They are produced by some of the most energetic and dramatic phenomena in the cosmos, including black holes, neutron stars and supernovae. The Laser Interferometer Gravitational-wave Observatory is on course to detect gravitational waves by using a device called laser interferometer, in which the time it takes light to travel between suspended mirrors is measured with high precision using controlled laser light. The two LIGO interferometers are the world's largest precision optical instruments and among the most sensitive scientific instruments on the planet. The discovery of gravitational waves will help to address a number of fundamental questions in physics, from the evolution of stars and galaxies to the origin of dark energy and the nature of spacetime itself. These developments will open an exciting new window on the Universe, heralding the arrival of gravitational wave astronomy as a revolutionary, new observational field.

References:
Thursday

October 22, 2009

4:00 PM

ILB Room 250

### Millimeter-wave and Terahertz Physics and Sensing Applications

The millimeter-wave and terahertz regions of the electromagnetic spectrum have a long and rich history in the area of high-resolution, gas-phase molecular spectroscopy that is based on well-established physics and the continuous advancement of technology over the past 40 years. This has led to the detection of molecules in space and the ability to monitor molecules in the upper atmosphere that are associated with stratospheric ozone chemistry. This spectral region also possesses a unique combination of attributes that include high transmission through most dielectric materials along with the ability to develop imaging systems, properties associated with the microwave and infrared/optical regions of the spectrum, respectively. Due to these advantages, several terrestrial applications under development include radar systems for the standoff detection of human vital signs for triage and imaging systems for non-destructive evaluation. However, progress in the development of these applications remains slow due to the lack of affordable commercial technologies, leading to both technological and scientific gaps. This talk will discuss the basic underlying physics for each of these applications as well as a discussion of emerging technologies and commercial opportunities.

References:
• D. T. Petkie, C. Benton, E. Bryan, Millimeter-wave radar for vital signs sensing, Proceedings of SPIE: Radar Sensor Technology XIII, 7308 , 73080A-73080A-5 (2009).
• D. T. Petkie, C. Casto, F. C. De Lucia , S. R. Murrill, B. Redman , R. L. Espinola , C. C. Franck, E. L. Jacobs , S. T. Griffin, C. E. Halford, J. Reynolds, S. OBrien, and D. Tofsted, Active and Passive Imaging in the THz Spectral Region: Phenomenology, Dynamic Range, Modes, and Illumination, Journal of the Optical Society of America B, 25, 1523-1531 (2008).
• D. T. Petkie, P. A. Helminger, B. P. Winnewisser, M. Winnewisser, K. W. Jucks, and F. C. De Lucia, The Simulation of Infrared Bands from the Analyses of Rotational Spectra: The 22 \mu Bands 2V9-V9 abd V5-V9 of HNO3, Journal of Quantitative Spectroscopy and Radiative Transfer, 92(2), 129-141 (2005).
Thursday

September 24, 2009

4:00 PM

ILB Room 250

### Gauge Theory and Fiber Bundles

There are four known forces in nature. All of them can be described by a class of theories called Gauge Theories. Fiber bundles are the mathematical structures behind gauge theories. In this colloquium, I will first explain what a gauge theory is using electromagnetic theory as an example and will also explain non-abelian gauge theories using Quantum ChromoDynamics as an example. After that I will explain the idea of gauge invariance and the consequence of requiring it in a theory. Next I will explain what fiber bundles are with some example. After that I will make connection between the fiber bundle structure and gauge theories. I will end with some current research problems in the field of research.

References:
• Equivalence of Minkowski and Euclidean Field Theory Solutions Authors: Khin Maung Maung, Charles A. Hill, Michael T. Hill, George DeRise arXiv:hep-ph/0302228
Thursday

April 16, 2009

4:00 PM

ILB Room 250

### Open Science Grid: Linking Universities and Laboratories in National Cyberinfrastructure

A collaboration of physicists and computer scientists from U.S. universities and national laboratories has since 1999 conducted a multifaceted R&D program aimed at building a national grid-based "cyberinfrastructure" to serve large-scale scientific research. This collaboration led to the creation of Open Science Grid consisting of more than 75 sites, 30,000 CPUs and serving particle physics, gravitational wave searches, digital astronomy, genome databases, nanoscience, functional magnetic resonance imaging, etc. OSG also links campus and regional grids and is a major component of the Worldwide LHC Computing Grid (WLCG) that handles the massive computing and storage needs of experiments at the Large Hadron Collider. This collaborative work has provided a wealth of results, including powerful new Grid tools and services; a uniform grid middleware packaging scheme (the Virtual Data Toolkit) that simplifies grid deployment across many sites; integration of complex Grid tools and services in large science applications; multiple education and outreach projects; and new approaches to integrating advanced network infrastructure in scientific computing applications.

References:
• Paul Avery, "Open Science Grid: Building and Sustaining General Cyberinfrastructure Using a Collaborative Approach", Selected Papers from the Conference on Cyberinfrastructure for Collaboration and Innovation (Jan. 28-29, 2007), First Monday, firstmonday.org, June 2007.
Thursday

October 23, 2008

4:00 PM

ILB Room 250

### Taking Sides on Dark Energy

Dark energy appears to be the dominant component of the present mass-density of the Universe, yet there is no persuasive theoretical explanation for its existence or magnitude. While the simplest explanation might be Einstein's cosmological constant, there are other possibilities, including dynamical dark energy, modification of general relativity, or back reactions of inhomogeneities. Many feel that nothing short of a revolution in our understanding of physics will be required to solve the dark energy issue. After framing the dark-energy problem, I will discuss possible theoretical solutions, as well as an observational program to study the properties of dark energy.

References:
• Report of the Dark Energy Task Force. Andreas Albrecht et al. FERMILAB-FN-0793-A, Sep 2006. e-Print: astro-ph/0609591
• http://imagine.gsfc.nasa.gov/docs/science/mysteries_l1/dark_energy.html
Thursday

October 16, 2008

4:00 PM

ILB Room 250

### Physics at the High Energy Frontier: Connections Between the Quarks and Cosmos

Particle physics has been extremely successful in establishing the constituents of matters, understanding the role of symmetries, and building the standard model of particles and interactions that explains current collider observations with exquisite precision. We are now poised to open a window on a new unexplored energy region called the TERASCALE where we expect a revolution in our understanding of physics and unequaled opportunity for discovery. The Standard Model of particle physics predicts the existence of the Higgs boson, a particle that carries the Higgs field. The Higgs field, which is expected to permeate the entire Universe, explains why matter has mass since as a massless particle passes through the Higgs field it gains mass. I will present the latest results from the CDF experiment at the Tevatron on the search for the Higgs boson and trace the discovery path from the Tevatron to the next high energy frontier at the Large Hadron Collider.

References:
• Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV. T. Aaltonen et al., The CDF Collaboration, Phys. Rev. Lett. 100, 211801 (2008)
• Search for Standard Model Higgs Bosons Produced in Association with W Bosons T. Aaltonen et al., The CDF Collaboration, Phys. Rev. Lett. 100, 041801 (2008)
Thursday

September 18, 2008

4:00 PM

ILB Room 250

### Past and Present in High Energy Physics

I shall give a very general overview of experimental particle physics, where we started from and where we are today. I will concentrate on the major collider detectors in the world at the Fermi National Accelerator Laboratory in Batavia, Illinois and the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. I shall also emphasize why this research is so important to the growth of a society and how undergraduate students in any science discipline can learn and contribute to this effort.

References:
• Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96-TeV. By D0 Collaboration (V.M. Abazov et al.). Published in Phys.Rev.Lett.100:192004,2008.
• CMS technical design report, volume II: Physics performance. By CMS Collaboration (G.L. Bayatian et al.). Published in J.Phys.G34:995-1579,2007.
Friday

March 28, 2008

4:00 PM

ILB Room 250

### Quantum Brownian Motion

The formalism of quantum open systems, as originally put forth by Feynman and Vernon, provides a framework for tackling many difficult problems in quantum mechanics. Key among these are (1) extending the kinetic theory of Brownian motion into the quantum domain and (2) giving exact models of dissipation in quantum systems, given that unitary dynamics would typically forbid energy loss and irreversible dynamics. This talk will give a general introduction to Quantum Brownian Motion and discuss some of the more recent results.

References:
• R. P. Feynman, F. L. Vernon, Ann. Phys. (N.Y.) 24, 118 (1963) A. O. Caldeira, A. J. Leggett, Physica A 121, 587 (1983). B. L. Hu, J. P. Paz and Y. Zhang, Phys. Rev. D 45, 2843 (1992). C. H. Fleming, B. L. Hu, A. Roura, arXiv:0705.2766 [quant-ph]
Thursday

March 20, 2008

4:00 PM

ILB Room 250

### Grid Computing and the CMS Experiment at the Large Hadron Collider

In recent years Grid Computing has evolved into a reliable and robust means of providing scientific communities with convenient access to unprecedented amounts of computing. In the US the Open Science Grid (OSG) was developed in part to support one these communities, namely scientists working on the Large Hadron Collider (LHC) experiments at CERN near Geneva, Switzerland. With help of grid computing these communities are now poised to explore some of the most profound questions about the nature of mater, energy and the very fabric of space time. In this talk I will introduce the concept of grid computing. I will then describe a current implementation, the OSG highlighting its most important components and illustrate how these together form a computing grid. I will then describing how the OSG and its European counterpart the EGEE were used in a recent large scale world-wide computing and data movement exercise conducted by the Compact Muon Solenoid experiment one of the four LHC experiments.

References:
• I. Foster, J. Gireraltowski, S. Gose, N. Maltsev, E. May, A. Rodriguez, et al., 2004, The Grid2003 Production Grid: Principles and Practice
Thursday

October 25, 2007

4:00 PM

ILB Room 250

### Gyrokinetic Particle-in-Cell Simulations of Strong Poloidal Flow Radial Gradient and Parallel Nonlinearity Effects on Toroidal Ion Temperature Gradient Driven Turbulence

Nonlinear gyrokinetic numerical calculations have been performed with the three-dimensional, global, toroidal, nonlinear, particle-in-cell, delta-f, massively parallel UCla-CANada (UCAN) code. Their purpose is to study the effects of the parallel nonlinearity and of strong (externally imposed) sheared flow radial gradient corrections on ion temperature gradient driven turbulence (ITGDT) in tokamaks. These calculations show that the strong flow corrections reinforce the powerful stabilizing effects of sheared poloidal flows on the saturation level of the fluctuations and on the heat flux they produce. The re-activated parallel nonlinearity, in combination with zonal flows generated through Reynolds stress by the fluctuations themselves, leads to an apparent quantitative reduction in saturation level and heat flux. This reduction does however decrease with increasing system size at fixed ion Larmor radius, i.e. with diminishing rho.

References:
• L. Villard, S.J. Allfrey, A. Bottino, M. Brunetti, G.L. Falchetto, V. Grandgirard, R. Hatzky, J. Nhrenberg, A.G. Peeters, O. Sauter, S. Sorge and J. Vaclavik, Full radius linear and nonlinear gyrokinetic simulations for tokamaks and stellarators: zonal flows, applied E x B flows, trapped electrons and finite beta, Nucl. Fusion, 44 No 1 (January 2004) 172-180
• L. Villard, P Angelino, A Bottino, S J Allfrey, R Hatzky, Y Idomura, O Sauter and T M Tran, "First principles based simulations of instabilities and turbulence", 2004 Plasma Phys. Control. Fusion, 46 B51-B62.
Friday

November 2, 2007

3:30 PM

ILB Room 240

### Hunting for New Physics

I will begin with an introduction to the Standard Model(SM) of particle physics. Though highly successful, there are many unanswered questions in the Standard Model. It is believed that some "new physics"(NP) must be there to resolve the SM puzzles. I will discuss how one can search for this new physics at present and future experiments such as the B factories and the LHC.

References:
• Is there New Physics in B Decays? Alakabha Datta (Mississippi U.) . UMISS-HEP-2007-01, Jan 2007. 8pp. Talk given at 2nd Annual Theory Canada 2 Conference, Waterloo, Ontario, Canada, 7-10 Jun 2006. e-Print: hep-ph/0701172
• The B to pi K puzzle and new physics. Seungwon Baek, Philippe Hamel, David London (Montreal U.) , Alakabha Datta (Toronto U.) , Denis A. Suprun (Brookhaven) . UDEM-GPP-TH-04-128, Dec 2004. 4pp. Published in Phys.Rev.D71:057502,2005. e-Print: hep-ph/0412086
Thursday

November 15, 2007

4:00 PM

ILB Room 250

### Review of Triboluminescence Research

Luminescence induced by mechanical stress is called mechanoluminescence (ML) or triboluminescence (TL). TL is a commonly encountered phenomenon, with approximately 50% of known crystals exhibiting such tendencies. The most commonly known example of a TL material is Wint-O-Green Lifesavers. If stressed, atriboluminescent crystal produces local regions with charge imbalances. Several mechanisms may then occur to produce light. It is possible for the charge imbalance to be sufficient to cause a dielectric breakdown of the surrounding gas, producing light. It is also possible for the emission of light from a dielectric breakdown to excite the triboluminescent material. A charge imbalance can also generate electroluminescence. The impacts are a possible source of stress to the crystal and create TL light.

References:
• N.P. Bergeron, W.A. Hollerman, S.M. Goedeke, M. Hovater, W. Hubbs, A. Fichum, R.J. Moore, S.W. Allison, and D.L. Edwards, Experimental Evidence of Triboluminescence Induced by Hypervelocity Impact, International Journal of Impact Engineering, 33 (1-12), 91-99 (2006).
• W.A. Hollerman, S.M. Goedeke, N.P. Bergeron, C.I. Muntele, S.W. Allison, and D. Ila, Effects of Proton Irradiation on Triboluminescent Materials Such as ZnS:Mn?, Nuclear Instruments and Methods in Physics Research, B241, 578-582 (2005).

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