Department of Physics and Astronomy
Seminars/Colloquia, Spring 2004

Abstracts of Talks

Dr. Tibor Torma Department of Physics and Astronomy University of Mississippi CCD Astrophotography at the Kennon Observatory Prof. Torma will discuss astrophotography at the Kennon Observatory using a Charge Coupled Device (CCD) camera. The CCD chip is cooled with a Peltier device to allow long exposures with low noise. Multiple photographs though different filters have been used to generate color photographs. A fast tip/tilt mirror corrects in real time for atmospheric distortion and tracking errors. Photographs will be shown of galaxies, star clusters, nebula, supernova explosion remnants, comets, asteroids, and planets including Pluto taken by Dr. Torma and his students.

Dr. Jill C. Tarter Director, Center for SETI Research Bernard M. Oliver Chair for SETI SETI: Pulling Signals Out of Noise A recent series of workshops has laid out a roadmap for SETI research for the next few decades. Three different approaches were identified. 1) Continue the radio search; build an affordable array from consumer market components, expand the search in frequency, and increase the target list to 100,000 stars. This array will also serve as a technology demonstration and perhaps enable the international radio astronomy community to realize an array that is a hundred times larger and capable (among other things) of searching a million stars. 2) Begin searches for very fast optical and infrared pulses from a million stars. 3) As Moore's Law delivers increased computational capacity, build an omni-directional sky survey array capable of detecting strong, transient, radio signals from billions of stars. SETI could succeed tomorrow, or it may be an endeavor for multiple generations. We are, after all, a very young technology in a very old galaxy. While our own leakage radiation continues to outshine the Sun at many frequencies, we remain detectable to others.   When our use of the spectrum becomes more efficient, it will be time to consider deliberate transmissions and the really tough questions: Who will speak for Earth? What will they say? Maybe by then we will be old and wise enough to find some answers.

Dr. Jill C. Tarter Director, Center for SETI Research Bernard M. Oliver Chair for SETI Life, the Universe, and SETI* In a Nutshell *Search for Extraterrestrial Intelligence Another summer, another "blockbuster" movie about aliens... but do they really exist? The real scientific search for evidence of life, and particularly intelligent life, elsewhere in the cosmos is just as exciting as the "reel" version, and a lot more logical. So far, we have only life-as-we-know-it to guide our speculations and observations. But new technologies, a new appreciation of the tenacity of life and a growing respect for the world of microbes, new spacecraft and missions, and new observatory facilities are rapidly expanding our viewpoint and surprising us. We can expect more surprises. In the next few decades we will take a much closer look at the places within our solar system where liquid water (even vast oceans) may exist and harbor life. We will probe the closest stars to see if other 'Earths' and 'biospheres' exist. SETI will broaden its strategies and extend its range out into the galaxy, looking for evidence of someone else's technology. We don't know what we will find; that's part of the excitement.

Dr. Benjamin Harms Department of Physics and Astronomy University of Alabama - Tuscaloosa Searching for Evidence of Strings in the Electromagnetic Radiation from Stars One of the outstanding problems in high energy physics is the search for experimental tests of string theory. Since string theory predicts the existence of a scalar form of gravity, called the dilaton, observing evidence for the existence of the dilaton would lend support to the viability of string theory as a description of the world in which we live. To test the existence of the dilaton we have studied the propagation of classical electromagnetic waves on the simplest four-dimensional spherically symmetric metric with a dilaton background field. Solutions to the relevant equations have been obtained perturbatively in a parameter which measures the strength of the dilaton field (hence parameterizes the departure from Schwarzschild geometry). The loss of energy from outgoing modes has been estimated as a back-scattering process against the dilaton background, which would affect the luminosity of stars with a dilaton field. The radiation emitted by a freely falling point-like source on such a background has also studied by analytical and numerical methods.

Dr. Will Marchant Space Sciences Laboratory, University of California - Berkeley The Cosmic Hot Interstellar Plasma Spectrometer Spacecraft (CHIPSat) On January 12th, 2003, the Cosmic Hot Interstellar Plasma Spectrometer Spacecraft (CHIPSat) launched successfully from Vandenberg Air Force Base as a secondary payload on a Delta II booster. CHIPSat completed commissioning in February 2003, and is now a fully operational observatory. The main science objective is to measure extreme ultraviolet emissions from the interstellar medium. Data on the distribution and intensity of these emissions allow scientists to test competing theories on the formation of hot interstellar gas clouds surrounding our solar system. CHIPSat is the first satellite in NASA's University-class Explorers Program (UNEX) to make it to orbit. The UNEX program was conceived by NASA as a new class of explorer mission charged with demonstrating that significant science and/or technology experiments can be performed with small satellites, constrained budgets and limited schedules. This talk presents the CHIPSat design, discusses the on-orbit performance to date, and provides lessons learned throughout the project.

Dr. Steve Stinnett Department of Physics and Astronomy Mississippi State University Micromagnetic Calculations of Magnetic Reversal in Single Fe Nanoparticles Magnetic materials are ubiquitous in today's society, particularly in computer and high tech applications such as hard drives and MRAM. As these devices are designed to operate at frequencies > 1 GHz, understanding the reversal in these materials becomes crucial. The basic approach of micromagnetics is to discretize a system into a series of sites with uniform magnetization density, Ms. Each site is then governed by the stochastic Landau-Lifshitz-Gilbert equation which is integrated to give the time evolution of the system. Interactions and thermal effects are included via effective fields which add to the applied magnetic field at each site. Results will be presented on single Fe nanoparticles using two different models and compared with experimental results from other researchers.

Alex Melnitchouk Department of Physics Brown University Search for the Higgs Boson We discuss the role that the Higgs boson plays in the Standard Model (SM) of elementary particles. Some extensions of the Standard Model are considered as well. An overview of the Higgs search is presented with an emphasis on the Tevatron proton-antiproton collider. In particular, we discuss Higgs physics program at the DØ experiment highlighting the search for the non-SM Higgs in the h → gg channel.

Dr. Satya Nandi Department of Physics Oklahoma State University Experimental String Theory and Extra Dimensions Current theoretical development in the framework of string theory requires the existence of extra dimensions of very small sizes, in addition to the three usual spatial dimensions. In this talk, I will briefly outline the theoretical arguments for this, and then describe how the existence of such new dimensions can be established via gravitational force measurements, astrophysical experiments and looking for new phenomena in upcoming high energy colliders,

Shaohua Fu Department of Physics Columbia University Search for Leptoquarks with the DØ Detector at Fermilab Experimental particle physicists have searched for clues of physics beyond the Standard Model for decades. Leptoquarks are hypothetical particles that are predicted in many extensions to the Standard Model and they connect the lepton and quark sectors. Since March 2001, the Fermilab Tevatron has begun its upgraded Run II proton-antiproton collisions at the center-of-mass energy of 1.96 TeV. This talk will describe a direct search for leptoquarks in the dielectron + dijet channel using the DØ detector at Fermilab.

Dr. John Latham National Center for Atmospheric Research Boulder, Colorado Amelioration of Global Warming by Controlled Enhancement of the Albedo and Longevity of Low-Level Maritime Clouds A technique is proposed for controlled enhancement of droplet concentrations in low-level maritime clouds, with corresponding increase in their albedo and longevity, thereby producing a cooling effect. It involves dissemination at the ocean surface of small seawater droplets which act as cloud condensation nuclei (CCN). It appears to be quantitatively adequate and technologically feasible. Control of the level of cooling seems achievable. It has low ecological impact.

Dr. Scott D. Sommerfeldt Department of Physics & Astronomy Brigham Young University Acoustic Energy Density: Measurement and Applications The most common measurement made in acoustics applications is the acoustic pressure, due to its simplicity. Much can be learned about a source and its radiated acoustic field from acoustic pressure measurements, but additional insight can be obtained from other measurements. One such example is the acoustic intensity measurement, which can be used for sound power measurements and source localization and identification. In recent years, we have been exploring acoustic energy density, and how it can be used to extract information regarding the acoustic field. In this presentation, several measurement probes we have developed for measuring acoustic energy density will be discussed. In addition, I will discuss applications of energy density measurements that we have been investigating. These include the use of near field acoustic energy density measurements to reconstruct the far field acoustic radiation field, from which the directivity and sound power can be estimated. Energy density measurements have also proven very useful in active noise control applications, and some of our work using energy density in active noise control will be discussed.

Dr. Gerard Buskes Department of Mathematics University of Mississippi Pssst ....., can you keep a secret? In this talk we will discuss the Problem of the Two Jars, Fermat's Little Theorem, and Sun-Tzu's Chinese Remainder Theorem in order to present both the method of RSA encryption as well the proof of why it works.

Dr. Marco Cavaglia Department of Physics and Astronomy University of Mississippi Physics with Friendly Black Holes of Known Mass at a Muon Collider If small extra dimensions exist, black holes may be created and observed via Hawking radiation [1] at very high energy particle colliders. The lifetimes are expected to be 10-26 seconds. This process may already be occurring in very energetic cosmic ray showers. Small extra dimension cause Newton's 1/r2 force law to be modified at small distances. Unlike proton or electron colliders, muon colliders can, in principle, produce black holes of known mass. This opens the possibilities of measuring quantum remnants, gravitons as missing energy, and scanning production turn on. [1] S. W. Hawking, Commun. Math. Phys. 43 (1975) 199;      S. W. Hawking, Phys. Rev. D13 (1976) 191.