Department of Physics and Astronomy
George Mason University, Fairfax

Spring 2005 Schedule --

Applications of the Continuity Statistic: Determining Functional Relationships Between Real Systems in Ecology, Physics and Engineering

Abstract: The continuity statistic, described by Pecora, Carroll and Heagy in 1995, has already been proven to be a valuable tool to test the existence of continuous functions between nonlinear systems that are reconstructed from experimental data. Here we describe a noise-tolerant formulation of the continuity statistic, and show several examples of new applications of the statistic to damage detection in structures, detection of spatial coupling in an ecological system, and detection of generalized synchronization in lasers. We also introduce a new statistic based on Holder Continuity. While the Continuity Statistic tests for a continuous functional relationship, the Numerical Holder Test considers differentiability of the proposed relationship between reconstructed systems.

Can Superstring/M-theory Be Seen in the Heavens?

Abstract: An introduction to Superstring/M-theory via the use of representative imagery of its mathematics as well as its analytical basis is given. These are used to motivate the modifications that super-sting/M-theory induces to the Einstein view of spacetime dynamics.

George Mason University's First Observatory-The Herschel Observatory

Abstract: In 1975, GMU's observatory and a 12.5 inch cassegrainian telescope were dedicated during an Astronomy Week that attracted more than 600 visitors. This was the conclusion of four years of work. The major designers and builders of the telescope and observatory were Chipper Petersen Whalan, Bob Veenstra, and John Whalan who were students at GMU. A pigsty left over from the original farm was transformed into a rolling-roof observatory. The telescope was the second largest in Virginia, and the third largest in the Washington, D.C. area. The observatory was in use until 1979 when it was removed to make way for the Field House. John Whalan will provide a historical perspective and describe the designs of the telescope and observatory.

Comparison of the observational data with the Global Climate Models

Abstract: There is a massive worldwide effort to develop General Climate Models to explain and predict the climate. They all predict global warming as anyone who follows the news knows. We can not know the future but we can ask if these models can explain the recent past--the last 25 years. We compared 4 independent observational data sets against the 3 leading models. The models disagree with the observations---even in sign. Using the principles of the scientific method one concludes that the models are wrong. From our other studies involving the seasonal cycle and more recently the Mt. Pinatubo volcano climate event we suggest that the models have response times that are too long and additionally have omitted negative feedback processes.

Rediscovering Physics

Abstract: As a part of the NVCC Sabbatical Program, in the spring of 2004 I have spent several weeks each with 1) Physics Education Group and Quantum Electronics Lab of Professor Eric Mazur at Harvard University, Cambridge, MA; 2) National Thomas Jefferson Electron Accelerator Facility, Newport News, VA; 3) National High Magnetic Field Laboratory, Tallahassee, FL. I will talk about the highlights of the current physics research there, and how it may relate to undergraduate teaching, from the point of view of an educator who himself was removed for a while from active research.

A Vision For The Next Generation Deep Space Network: The Next 100 Years

Abstract: Over the coming decades NASA is planning an ambitious program of human and robotic exploration that will involve spacecraft traveling to the moon and the distant solar system. This will require communication capabilities with Earth that are a thousand to a million times better than today. NASA must develop a comprehensive strategy for deep space communications that meets the forthcoming dramatic increase in mission needs in a reliable and cost effective manner. These goals can be achieved through a three-part strategy employing cutting-edge technology:

• Radio communication with large arrays of small antennas used for all missions, large and small, and new and old;
• Optical communication for transferring extremely high data rates on “trunk lines” from Mars or the Moon to Earth, or for special missions; and
• Orbital relay satellites at the Moon, Mars, and perhaps other planets.

These three elements of the future deep space communication system are complementary, and all are required.

Relativity -- the adventures of Alice and Bob

Abstract: The Pirelli Tire Company in honor of the Einstein 1905 Centennial is offering a major prize to anyone who comes up with the best 5 minute interactive multimedia presentation explaining special relativity to a layperson -- see http://www.pirelliaward.com/einstein.html The judging panel consists of a well-known physicist, a science journalist, and a student. I plan to enter the competition by developing something this summer together with two students, and I am desperately seeking constructive criticism of my preliminary design -- before I turn it over to the student programmers! This seminar will be more in the nature of a brainstorming session that critiques my design, rather than a lecture. Anyone else who may be considering submitting their own entry is asked not to come.

Building laboratory models of planetary cores

Abstract: We probe aspects of the dynamics of fluid flows in planetary cores using experiments in liquid sodium, liquid helium, liquid nitrogen or water (not of course mixed together!). Key to these several experimental devices is exploring how turbulence is effected by rotation, magnetic fields or both. As both add some measure of elasticity to the flows, several types of oscillatory behavior are observed depending on the force balances involved. Ordering the Coriolis, Lorentz, and Inertial forces is key to understanding the complicated states observed. While these experiments are undertaken in part to understand the geodynamo, they have led to a number of different first observations, including the magnetorotational instability, and inertial waves in both spherical Couette flow and decaying turbulence in cryogenic flows. These different approaches to using laboratory experiments are opening up a new direction to understanding the dynamics of the Earth's outer core and other Planetary interiors.

Three Blind Mice and How the Clock (SCN) Sees

Abstract: It was believed as of a decade ago that there were four photoreceptors in the eye, the three cones and the rods. These were the cells that initiated the vision process in vertebrates. However, it was discovered that mice deficient in rods, cones or both, were able to entrain and shift their circadian cycles and the only way to stop the response was the removal of the eyes. There were a series of human experiments on melatonin suppression as a function of wavelength which indicated that the SCN (suprachiasmic nuclei or clock) response was initiated by a new opsin photopigment distinct from the visual system set.

Physics was able to help in the search for the new receptors which are located in the ganglion layer of the retina. The process is based on photon number flux, transducing the signal and isomerase for returning to the sensory state. The new photopigment, melanopsin has a maximum response at 479 nm (blue). The discussion will explore the action function for photopigments and circadian response and contrast that with the visual response function. The two receptor systems are not independent and the pupil constriction function is associated with the new photoreceptor.

The consequences of these processes have clinical effects on treatment of sleep disorders, jet lag and alertness. In addition, the circadian administration of medication may be more effective by utilizing these results especially for chemotherapy.

TBA

Abstract:

A Curiouser and Curiouser Quantum Paradox

Abstract:

In this talk, I will review a Gedanken-experiment in which, following one line of reasoning, an electron is said to be definitely in one location. On the other hand, following an alternative reasoning, the same electron is said to be definitely in another location.

As with many well-known quantum paradoxes, the paradoxical effects appear only when one discusses results of experiments which do not actually take place. That is, when the experiments do take place, they disturb the system in such a way that the paradoxical effects disappear. Hence the paradox is usually dismissed as non-physical. Rather than dismissing the paradox, I argue that when a new set of measurements developed by our group is applied to the paradox, then strange and surprising experimental outcomes are obtained. E.g. our theory predicts that an actual measurement will indicate a negative number of particles. Actual experiments were subsequently performed and their results were in very good agreement with our theoretical predictions.

These paradoxes point to a deeper structure inherent to quantum mechanics which obeys a simple, intuitive, and self-consistent logic. (see Aharonov...Tollaksen, Phys. Lett. A, 301, p. 130-, 2002; and New Scientist cover story "They said it couldn't be done, but now we can see inside the quantum world," May 2003).

Schedule for previous years: Fall01 schedule,Spring02 schedule,Fall03 schedule,Spring04 schedule,Fall04 schedule