Article Index

This page lists all of the abstracts for the Fall 2010 colloquium series. For dates and speakers, see Colloquium Fall 2010.

Dr. Alex Small

Cal Poly Pomona

“Optics Beyond the Diffraction Limit: How to see tiny things in cells”

Recent experimental work has shown that it is possible to beat the diffraction limit in fluorescence microscopy, and obtain images of cells with nanometer resolution. These techniques usually involving randomly switching molecules on and off, so that only a fraction are in an “activated” (i.e. light-emitting) state at any given time. Although each molecule still produces a diffraction-limited image, its image does not overlap any other molecules, so the molecular position can be inferred with noise-limited accuracy. As the density of activated molecules increases, a faster experiment becomes possible, but the possibility of errors increases. We have formulated a statistical model of this process, and found that there is a maximum possible activation probability, and hence a maximum activation rate. Interestingly, this maximum activation probability is related to the performance of the algorithms used to analyze the data. We have also proven the existence of an optimal image acquisition scheme in the case of bleaching, with an error rate that can be predicted from the imaging speed and the algorithm performance. Finally, we have begun bench-marking common image analysis algorithms, and are using insights from our model to develop image analysis algorithms with comparable performance and better speed.

Mr. Chris Francis

Cal State Fullerton

"MS Project: Measuring scattered light from Advanced LIGO optics"

This talk describes Chris Francis' Master's project research on measuring scattered light from LIGO optics using an imaging scatterometer.

Dr. Andreas Bill     

CSU Long Beach     

"Development of the Grain Size Distribution During the Crystallization of a Solid"

The microstructure of a solid impacts in important ways its electronic, optical or magnetic properties. A quantitative characterization of a material’s granularity is thus essential for tailoring its functionality. We propose a theory for the grain size distribution of an amorphous solid undergoing crystallization, and derive an analytic expression for the case of random nucleation and growth processes in d dimensions (d = 1,2,3). The solution describes the time-dependence of the distribution from early stages to full crystallization. Both isotropic and anisotropic growth rates are considered. Particular emphasis is set on analyzing how the time-dependence of both the effective nucleation and growth rates affects the final distribution. Remarkably, for certain effectives rates the distribution evolves into a lognormal form in the asymptotic limit of large times. An application of the theory to semiconductors is also presented.

Dr. Michael Larson     

Northrop Grumman Aerospace Systems   

"Atomic Frequency Standards"

Ever wonder how an atomic clock works, or why you should care? What is time, and why is it important to measure? In the 1700s the British government decided the problem of accurately and reliably measuring time to aid the navigation of its ships was so important they offered a prize which in today’s money would be >$4 million. Isaac Newton worked on solutions to the problem using celestial observations, but in the end it was a talented clockmaker named John Harrison who developed the most practical solution to the problem and collected more than half the prize money. Clocks have come a long way since then and with every improvement comes new applications with even more demanding requirements for accurate time measurement. This briefing presents the ideas behind, importance of, and techniques for measuring time. Specifically the history behind, general principles of operation, and design for cesium beam clocks will be given. For background a discussion of what time is and its importance in the areas of cell phones and communication networks, power distribution, and navigation will be presented. Also presented will be a short history of the relevance of time to navigation and how that problem inspired John Harrison and a Isaac Newton, or maybe it was the more than $4 million in prize money.

Biography: Dr. Michael Larsen Earned his B.S. from California State University, Fullerton in 2000, and his Ph.D. from the University of Wisconsin, Madison in 2007. In September 2007 he joined the Advanced Technology & Strategic Applications group in the Navigation Systems Division of Northrop Grumman. He is the lead physicist for the DARPA funded Nuclear Magnetic Resonance Gyroscope program and co-principle investigator on the Paramagnetic Magnetometer (PMM) and Magneto-Optical Atom Trap (MOAT) IRAD projects. His research includes work on inertial instruments, electric and magnetic field sensors, and atomic frequency standards.

Dr. Geoff Steeves     

Caltech & University of Victoria     

Calling All Astronauts

Last year, while working at Caltech, I competed to become an astronaut for the Canadian Space Agency. Through interviews, medical tests, fitness tests, aptitude tests and stress/survival tests, a field of 5351 qualified applicants was narrowed to 16 finalists and ultimately to two. As a top 16 finalist, I will describe the year-long campaign in detail and highlight some of the amazing and unusual challenges we faced. I will also discuss how my background as a physicist and commercial pilot aided me throughout the experience. Aspiring astronauts are encouraged to attend!

Dr. Duncan Brown     

Syracuse University     

"Gravitational-wave Astronomy with the Laser Interferometer Gravitational-wave Observatory"

Almost all of our knowledge of astronomy and astrophysics comes from observing the Universe with electromagnetic waves. Gravitational waves are one of the most remarkable predictions of Einstein's theory of General Relativity. These waves are ``ripples in the curvature of spacetime which carry information about the changing gravitational fields of distant objects. Gravitational-waves are analogous to electromagnetic waves, but because the coupling between gravity and matter is so much weaker than the coupling between light and matter, it is very difficult to generate detectable gravitational waves. To generate waves strong enough to be detectable with current technology needs extremely dense, massive objects, such as black holes and neutron stars, moving at speeds close to the speed of light. The first detection of gravitational-wave observations will open a new window on the Universe and establish the field of gravitational-wave astronomy.

The U.S. Laser Interferometer Gravitational-wave Observatory (LIGO) and its French-Italian counterpart Virgo are presently searching for gravitational waves. I will review the status of the search for waves emitted during the final moments of binary systems containing black holes and neutron stars. I will describe how information from numerical modeling of binary black holes is being used to improve current and future searches and discuss how observations of these systems will bring us new knowledge of both fundamental physics and astrophysics.

Dr. Jay Marx, LIGO Director     


"Gravitational Waves, a New Window on the Universe"

The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a facility dedicated to the detection of cosmic gravitational waves and pioneering of the new field of gravitational wave astronomy. This talk will describe the nature of gravitational waves, possible astrophysical sources of detectable gravitational waves such as merging pairs of black holes and neutron stars, supernovae and the big bang, how LIGO works, the current status of LIGO, and future plans for LIGO. Prospects for a coordinated international network of gravitational wave detectors that will function as a global gravitational wave telescope will also be described.

Dr. Tim Gay     

University of Nebraska   

"One Atom Too Many: An Atomic Physicist's Attempt To Learn About Simple Homonuclear Diatomic Molecules"

When a polarized electron collides with an atom, it can transfer its spin to the residual target. This angular momentum can subsequently be partitioned among the various atomic angular momenta nuclear and electronic spin and electronic orbital angular momentum. The way in which this happens can provide important details about the collision dynamics. Molecular targets complicate this picture, because they have another "reservoir" into which the angular momentum can go: nuclear rotation. Recent experiments involving collisions of spinning electrons and photons with molecules have produced some surprising new results, even thought the molecular targets are the simplest available -- homonuclear diatomics. New directions for experiments, for those with enough intestinal fortitude to consider further work with molecular targets, will be proposed.

"The Physics of Football"

This talk discusses a series of one-minute physics lectures given to the ~ 8 x 104 fans that attend the University of Nebraska home football games. The lecture topics range from gyroscopic motion to ionizing collisions between linebackers and I-backs. The problem of simultaneous edification and amusement of the fan in the stands is considered.

From 1999 until 2004, Tim Gay, a Professor of Physics at the University of Nebraska - Lincoln, taught the largest physics class in the world – the 78,000 fans that attend the University of Nebraska Cornhuskers home football games in Memorial Stadium. During a pause in the action, Gay’s lessons were shown on the giant television screens at either end of the field. They ranged in length from forty-five seconds to two minutes, and covered such topics as Newton’s Laws of Motion (blocking and tackling), projectile motion (kicking and punting), kinematics (open-field running), and the ideal gas law (why not fill the football with helium to get better hangtime?). Laboratory demonstrations featured Professor Gay being tackled by 370 pound lineman, pummeled with a sledgehammer as he lay on a bed of nails, and learning the finer points of passing from Heisman trophy winner Eric Crouch.

Gay’s work has been featured on ABC World News Tonight with Peter Jennings, ESPN’s Cold Pizza, and front page stories in the Wall Street Journal and the Tuesday Science section of the New York Times, as well as in People Magazine, ESPN Magazine, the Boston Globe, the Washington Post, and a variety of other television and radio outlets.

In 2001, Gay was hired by NFL Films to write and appear in a series of 5-minute television segments for their show NFL Blast! Blast! is a half-hour program shown in 190 foreign countries to familiarize its audience with the game of American football. The Football Physics segments on the show feature lectures and demonstrations by Gay and interviews with current NFL players. These segments aired starting in 2002, and ran through 2004.

Gay has also written a book, Football Physics, published by Rodale. It recently came out in a second edition retitled The Physics of Football published by Harper-Collins Paperbacks. Its target audience is high school students and football fans of all ages.

The Nebraska segments can be viewed on the Web: