Relativistic Quantum Mechanics

Peter Rolnick
Division of Science/Physics, Truman State University

Quantum Field Theory (QFT), the primary tool of elementary particle physics, replaces the idea of a particle with that of a field. A primary motivation for the development of QFT is that it incorporates both the ideas of quantum mechanics and the ideas of special relativity, so it can be applied to quantum systems moving at very high speeds. In 1949, Dirac (one of the architects of QFT) suggested a different approach for combining quantum and relativistic ideas, called Relativistic Hamiltonian Dynamics (RHD), in which quantum mechanical particles are "forced" to obey the rules of special relativity. Though not as popular as QFT, RHD allows us to combine quantum mechanics and relativity while still treating a particle as a particle. The result is that the potential energy of the particle (appearing only in the energy operator or "Hamiltonian" in non-relativistic quantum mechanics) gets "mixed into" other operators (for example, the momentum). I will go over the fundamental concepts underlying RHD: invariance with respect to a change of reference frame, and the properties of a quantum mechanical state, and I will explain the constraints that result from combining them.

From the Big Bang to the Future: A Modern View of Cosmology

Hume Feldman
Department of Physics & Astronomy, University of Kansas

Before there was science, there was cosmology. We have been asking ourselves questions about the origin of our world (the Universe) for thousands of years: How did it all start? How did it evolve? What will happen in the future? Now, for the first time in our history, we are able to answer these questions. What do we know about our Universe? How do we know it? How confident are we in this newly found knowledge? We will present the evidence for the Big Bang and follow the observational and experimental evidence to explore the history and future of the Universe.

The Highest Energy Cosmic Ray Puzzle: What Are They and Where Do They Come From?

Doug McKay
Department of Physics, University of Kansas

Recent proposals that the fundamental mass scale of gravity is about the same as that of the weak interactions opens many dramatic possibilities. I explore the consequences of strong gravity for the propagation and detection of high energy neutrinos originating in spectacularly energetic sources at cosmological distances from us. I'll review the origin of the Planck mass and corresponding time and length scales, then describe the impact of extending gravity to extra, compact spatial dimensions of macroscopic or near macroscopic size. I'll describe the resulting changes in the behavior of the one, purely weakly interacting particle we know, the neutrino, and what the changes mean for its detection.

The Development of Science: Progressive or Revolutionary?

Chad Mohler
Truman State University, Philosophy and Religion

Is science a discipline that over time has developed a single, increasingly refined picture of the physical world? Or is it more aptly characterized as a discipline that has evolved disjointedly, with sudden changes of perspective? Can we say there is progress in science? Is science creation or discovery? By looking at scientific theories whose concepts cannot be adequately expressed in the language of other scientific theories, I will address these questions and develop the view that science is both progressive and revolutionary, creation and discovery at the same time.

Advanced Lab Presentations on Current Issues in Experimental Physics

Kevin Haworth, Heather Molle, Jessica Rolwes, Cormac Smith
Truman State University, Science/Physics

Students in Advanced Lab II are required to make formal presentations based on an article about some current work in experimental physics. Kevin Haworth will be presenting on the recent experimental observation of quantum states for a neutron in a gravitational potential well. Cormac Smith will talk about the construction, capabilities, and research goals of the proton collider at CERN. Heather Molle will take a close look at how free-electron lasers work, the benefits and weaknesses of FELs, and their applications in physics and other fields. Jessica Rolwes will discuss the National Ignition Facility (NIF) currently under construction at Lawrence Livermore National Laboratory. This multiple laser may be the next step in creating fusion ignition; the bonding of two nuclei to form a new nucleus.

Wednesday, November 14, BT 251/2, 4:35 to 5:25 pm

High-temperature Superconductivity: Where are we Heading to?

Judy Wu
Department of Physics and Astronomy, University of Kansas

The discovery of high-temperature superconductivity has been regarded as one of the most important events of 20th century physics, generating a worldwide "HTS-fever" in research on these new materials and in search for newer superconductors. Now 15 years later, the mechanism of high-temperature superconductivity remains a hot topic and is predicted to lead to some of the most important physics in the 21st century. Meanwhile, commercial applications of high-temperature superconductors are appearing.

Wednesday, November 7, BT 251/2, 4:35 to 5:25 pm

The Accelerating Universe

Ta-Pei Cheng
Department of Physics & Astronomy, University of Missouri - St. Louis

This will be an introductory talk on the "new revolution in cosmology" -- the discovery that the Universe has been expanding at an accelerating rate. We shall explain the compatibility of this sensational observation with other recent major findings in cosmology -- the Universe has zero curvature (i.e., a flat universe), yet the density of luminous matter and dark matter together is measured to be less than "the critical density" associated with a flat universe, and some of the stars have been found to be older than the age predicted by a flat universe. We explain how all such surprising observation actually support each other and can be summarized as showing the existence of a non-zero "cosmological constant" [Lambda], first introduced by Einstein in his general relativistic field equation. Such a [Lambda] term corresponds to a constant energy density, a negative pressure, and a repulsive gravitational force. Finally, we discuss the so-called "cosmological constant problem" -- no known physics can give an estimate of [Lambda] that's even remotely correct.

Wednesday, October 31, BT 251/2, 4:35 to 5:25 pm

Student Summer Research Presentations

Tim Flanagan, Jessica Rolwes, Adam Woodson, and Tricia Youngquist
Truman State University, Science/Physics

Four 12-minute talks by Truman physics students on the work they did during their summer research experiences.

Wednesday, October 24, BT 251/2, 4:35 to 5:25 pm

Zeptosecond Games in Femtoland

Lee Sabotka
Department of Chemistry, Washington University

Two topics will be presented: (1) Our observation of Coulomb tides and (2) Our first attempts to observe component fractionation in a two component quantal system with non-uniform density.

A Coulomb tidal effect, which occurs on a femtometer scale and operates strongly for only several zeptoseconds, influences the breakup of complex (or cluster) nuclei evaporated from hot nuclear systems. This subject will be presented in a general framework requiring no prior knowledge of nuclear processes.

The rationale behind searching for neutron/proton fractionation between regions of nuclear material existing at different densities will be presented. There is a controlling legal (that is thermodynamic) authority and it is identical to that controlling component fractionation in a two component chemical system. In the nuclear case however the variation of the chemical potentials of the two species with density has a quantal origin. A first attempt to observe this phenomena will be discussed.

Friday, October 12, VH 1010, 12:30 to 1:20 pm
SPECIAL SCIENCE SEMINAR

A Visit With Astronaut Sandra Magnus

Sandra H. Magnus
NASA Astronaut

Dr. Magnus will talk on her work with the International Space Station.

Wednesday, October 3, BT 251/2, 4:35 to 5:25 pm

Tune In, Turn On, Drop Down or Planting RICE in the Antarctic icecap or Whatever happens to all those antennas that disappear from new cars?

David Besson
Department of Physics and Astronomy, University of Kansas

Among the most energetic cosmic rays incident on the earth are those which may be produced by either massive black holes which could exist at the centers of some galaxies (aka "Active Galactic Nuclei," or AGN), or perhaps Gamma-Ray Bursts (GRB). Additional ultra-high energy neutrinos may be produced by the (as-yet-unidentified) process responsible for the ultra-high energy cosmic rays observed in present Extensive Air Shower experiments, and anticipated for the future Auger Project. The Fly's Eye and Akeno Experiments have confirmed that particles of energy as high as 10²⁰ eV are, indeed, present in the cosmic ray flux, suggesting an enormously energetic, yet mysteriously invisible source close to earth. We describe a new experimental effort to detect ultra high energy electron neutrinos through their interactions with ice molecules in the Antarctic icecap, based on the principle of "radio coherence." Experimentally, we measure a long-wavelength (radiofrequency) pulse resulting from this interaction. A prototype experiment (Radio Ice Cerenkov Experiment, or RICE) presently operating as part of the larger AMANDA effort at the South Pole is described.

Wednesday, September 26, BT 251/2, 4:35 to 5:25 pm

Advanced Lab Presentations on Current Issues in Experimental Physics

Shawn Gilmore and Timothy Flanagan
Truman State University, Science/Physics

Students in Advanced Lab II are required to make formal presentations based on an article about some current work in experimental physics. Mr. Flanagan will review recent work on trapping light in microspheres and Mr. Gilmore will talk about the latest advances in measuring fundamental physical constants.

Wednesday, September 19, BT 251/2, 4:35 to 5:25 pm

Galaxy Clustering and the Fate of the Universe

Adrian L. Melott
Department of Physics and Astronomy, University of Kansas

I will argue that evidence on the evolution of clusters of galaxies points to a low-density Universe which will expand forever. Then I will turn to work in progress: In the next few years, we will map an appreciable fraction of the Universe by redshift surveys. Redshift surveys are based on the assumption that recession speed is proportional to distance, which is only true to first order. Motions of galaxies are induced by gravity as part of the ongoing process of structure formation. I will show that such motions tend to enhance structures apparently concentric around the observer's position, and argue that the strength of this effect will be a powerful new probe of the mass density of the Universe.

Thursday, April 19, MG 124, 4:35 to 5:25 pm

Quantum Mechanics for Fun and Profit

Carlos Stroud
Physics Department, University of Rochester

Quantum mechanics predicts phenomena which are quite contrary to our everyday experience in the macroscopic world. A quantum particle can simultaneously support properties that would appear to be contradictory, such as being in two places at once, or localized in one spot and spread out as a wave simultaneously. These effects have previously been thought to be confined to the microscopic world of atoms and particles, and observable only very indirectly. Recently laboratory tools have been developed that allow us to observe and control these esoteric effects very directly. The control of this "quantum weirdness" promises to allow some very practical new applications such as quantum computers that are more powerful than any normal computer that we can conceive, a communication system which cannot be bugged, even quantum teleportation. We will review progress in this exciting field at a level appropriate for those without any experience in quantum mechanics or advanced physics.

Wednesday, April 18, BT 251/2, 4:35 to 5:25 pm

Getting Inside an Atom: Imaging and Manipulation of Atomic Electrons

Carlos Stroud
Physics Department, University of Rochester

A series of experiments will be described in which a series of laser pulses are used to make atoms a millimeter in diameter, form a Schrödinger Cat State, an interferometer, and perhaps even a computer inside a single atom. The same laser pulses are used to image the electrons inside the atom and to explore the question: "How classical can a single atom be?"

Wednesday, April 11, BT 251/2, 4:35 to 5:25 pm

"You Mean it Really Works Like That?": The Connections that Students Sometimes Miss in Learning Physics

Jennifer Snyder
Department of Physics, University of Missouri-Kansas City

There are many reasons why some students have trouble learning physics. This presentation explores these problems from two points of view. The presentation begins with an overview of research on problem solving in general and how these results apply to the unique structure of physics knowledge. Next, the focus switches to examine how students' beliefs about the nature of physics affect how they learn. Both of these views explore the connections that people make between models and theories and the natural world.

Wednesday, April 4, BT 251/2, 4:35 to 5:25 pm

The Many-Body Problem in Physics

Michael Schulz
Physics Department, University of Missouri-Rolla

For the objective of understanding nature, essentially all research in physics has to address two fundamentally important aspects: 1) the basic interactions between pairs of two particles have to be known and 2) the time development of many-particle systems under the influence of these basic interactions has to be understood. The latter point is known as the Many-Body Problem in physics. Atomic collisions represent particularly suitable systems to study the Many-Body Problem because the underlying basic interaction (the electromagnetic interaction) is perfectly well understood and because every particle in the system is experimentally tractable. As an example, complete experiments on single ionization in ion-atom collisions will be discussed. It will be demonstrated that, in spite of several decades of intense and successful research, our understanding of the Many-Body Problem is still rather incomplete.

Wednesday, March 28, BT 251/2, 4:35 to 5:25 pm

Addressing Single Molecular Events Using the Atomic Force Microscope

Michel Grandbois
Department of Physics and Astronomy, University of Missouri-Columbia

Single molecule force spectroscopy, a new experimental approach that makes use of the atomic force microscope, was recently developed to manipulate single molecules and to investigate the mechanical properties of individual polymer strands. Entropy elasticity, molecular rearrangement, covalent bond stretching and bending as well as covalent bond rupture where measured on a single molecule basis. We have also investigated the forces involved in molecular recognition events for synthetic and biological molecular pairs.

Wednesday, March 21, BT 251/2, 4:35 to 5:25 pm

Electron Scattering as a Hadronic Probe

Wayne Polyzou
Department of Physics, University of Iowa

I will begin with a brief review of what physicists currently believe about the structure of hadrons (nucleons and mesons) in terms of constituent quarks. I will discuss why electron scattering is a useful tool for learning about the structure of of these particles. Finally I will discuss how theory and experiment are used to "see" quarks that are confined to hadrons. I will close with some of the challenges remaining for contemporary researchers..

Wednesday, February 7, BT 251/2, 4:35 to 5:25 pm

Experimental Atmospheric Science Using Wilson's Cloud Chamber

John Schmitt
Department of Physics and Cloud and Aerosol Sciences Laboratory, University of Missouri-Rolla

C. T. R. Wilson developed his cloud chamber over a century ago. It still is in use because it has capabilities that are not exceeded by any other instrument. The talk will discuss how the Wilson cloud chamber works, its application to basic experiments on how a vapor becomes a liquid (vapor to liquid homogeneous nucleation), its performance as a trace molecule detector (1 part in 10 to the 19th), and its proposed use as an ion detector in an attempt to understand the correlation between cloudiness in the atmosphere and the cosmic ray flux from our galaxy. A good time will be had by all.

Wednesday, January 31, BT 251/2, 4:35 to 5:25 pm

Electron Scattering and the Fundamental Constituents of Matter

William Klink
Department of Physics, University of Iowa

The scattering of electrons off complex targets provides a powerful tool for investigating the structure of the targets. In particular electron scattering provides clear evidence for the quantization of systems ranging from molecules and atoms through nucleons and nuclei. After a brief history of electron scattering some elementary symmetry arguments are used to show how relativistic models of quarks and nucleons can be constructed and tested against electron scattering data.

The Characterization of Physical Properties of the Heart Using Ultrasound

Steven Baldwin
Washington University Department of Physics and Truman alumnus

Ultrasonic imaging is an important and frequently utilized diagnostic tool used to characterize the condition of the heart. However, because the heart consists of muscle fibers oriented in specific directions, the ultrasonic images obtained depend upon the relative angles between the direction of the ultrasound propagation and the heart fibers. In this presentation current issues associated with the use of ultrasound to characterize the state of the heart will be discussed. Furthermore, specific results from studies designed to quantify the effects of fiber direction on the loss of ultrasonic energy in clinical images will be presented. These results may significantly influence the proper interpretation of quantitative measurements of heart characteristics such as those obtained with recently developed ultrasonic imaging contrast agents.

Thursday, November 2

How do we know what they know?

Brandt Hinrichs
Department of Physics, Drury University

A preliminary study of the formulation of student's mental models of electrical resistance in an introductory physics course. Questions asked include: "why is it interesting to study how students understand electrical resistance?", "how do students think about electrical resistance (after instruction)?", "how do I know what they are thinking?", "do they have mental models of the concept?", "what is a mental model?", etc. I conclude with some possible implications for educational strategies.

Wednesday, October 11

Journey to the Center of the Earth: The Bottom Half of Plate Tectonics

Michael E. Wysession
Department of Earth and Planetary Sciences, Washington University

Plate Tectonics changed the way we thought about the evolution of Earth's surface, but didn't help much with the confusion surrounding the evolution of the deep earth. Pictures of plate motions showed subducting slabs sinking into the mantle, and hot spot plumes reaching the surface, but omitted what happened in between. Modern seismology has since filled in this picture, finally completing the plate tectonic revolution that began 4 decades ago. New data combined with new techniques of analysis now shows a global cycle whereby subducted plates sink to the core-mantle boundary, heat up, and rise up again. The return flow upward occurs as wide and broad themal features, which reach the surface as hot spot plumes. The region surrounding the core-mantle boundary is now seen as being the most geologically variable and heterogeneous part of the earth following the lithosphere. As such, the core-mantle boundary can been seen as earth's "other" surface, and it possesses many geological processes that are analogous to those at the surface: topography, large lateral chemical and thermal variations, anisotropy, partial melting, and fluid-rock interactions.

Wednesday, October 4

Visualization of Proper Time in Special Relativity

Rob Salgado
Department of Physics, Truman State University

We present a new visualization of the proper time elapsed along an observer's worldline. By supplementing worldlines with light clocks, the measurement of spacetime-intervals is reduced to the "counting of ticks." The resulting spacetime diagrams are pedagogically attractive because they emphasize the relativistic view that "time is what is measured by an observer's clock."

Wednesday, September 27

Promoting Active Learning in the Classroom Using "Low-Tech" and "High-Tech" Methods

Kandian Manivannan
Department of Physics, Astronomy and Materials Science, Southwest Missouri State University

Physics education research has shown that active learning environments can be very effective in improving students' conceptual understanding of physics. I will discuss some of the techniques we have developed aimed at increasing active student participation in the classroom. These include a "Low-Tech" method that uses Flash Cards, as well as a "High-Tech" computer-based, easy-to-use wireless electronic feedback system, to receive instantaneous feedback from all the students in the classroom. These teaching strategies have transformed my classes into highly interactive, active learning environments. Without me even trying, my classes have become much more "alive" and fun, and students now enjoy the classes much more than the long and sleepy lectures!
Come prepared for a hands-on, interactive presentation that is guaranteed (but with no "money-back" promises) to keep you awake.

Wednesday, September 20

Timeless Reality: The View from Nowhen

Victor J. Stenger
Emeritus Professor of Physics and Astronomy, University of Hawaii

No basis for an arrow of time can be found in any of the laws of physics. All fundamental physical processes can happen in either time direction. On the scale of everyday experience, one time direction is highly more probable than the other for many observed processes, but this is the statistical result of the large number of particles involved and their largely random motions.
On the quantum scale, events are found to depend on the future as well as the past, which makes them seem very strange. Weird effects occur, such as particles appearing simultaneously at different places ("nonlocality"). These and other quantum paradoxes can be easily understood in terms of time symmetry. On the other hand, the time travel paradox, in which you go back in time and kill your grandfather, does not occur at the quantum level. Thus quantum time travel is not paradoxical.
Time symmetry at the quantum level makes it possible to draw a model of underlying reality that is simpler and more symmetric than the conventional view. This reality is timeless, with no beginning, no end, and no arrow of time. Observations at the smallest distances and highest energies reveal a picture of localized, discrete material bodies moving along definite spacetime paths in an otherwise empty void, with no fundamental distinction between past and future and no need to introduce "real" continuous fields. This is the picture revealed to us by the standard model of elementary particle and forces, which is fully consistent will all empirical data.

Tuesday, September 19: SPECIAL SCIENCE SEMINAR

Bioenergetic Fields: A Physicist's Perspective

Victor J. Stenger
Emeritus Professor of Physics and Astronomy, University of Hawaii

Energy therapies are based on the ancient notion that living matter possesses some special vital force or energy that is separate from matter. Today this energy is associated with electromagnetic or quantum fields. However, no evidence for any special vital forces, energies, or fields has ever been found. Modern physics has shown that energy and matter are the same thing and that no continuous fields exist. Quantum fields are composed of particles.
The current standard model of fundamental particles and forces successfully describes all current observations. Living matter is composed of the same particles acted on by the same forces. Quantum mechanics provides no basis for paranormal or holistic claims, medical or otherwise. Modern physics remains totally materialistic and reductionistic.
Reports of extraordinary claims should not be published unless the evidence is extraordinary. The violation of established physical law is sufficient to ignore such claims until extraordinary evidence is presented.