Bruce Thompson

Professor Emeritus, Physics and Astronomy
Specialty: Geophysics and Applied Physics

Research and student projects:

Building a MOT - By using carefully controlled lasers and magnetic fields, atoms can be slowed down from their normal frenzied activity and trapped as a extremely cold cloud. In the summer of 2009, Judith Olson '11 and I embarked on a project to build a Magneto-Optical Trap (MOT) apparatus. The MOT traps a cloud of Rubidium atoms at a temperature within a fraction of a degree of absolute zero. Judith worked on this project as her senior thesis for the BS degree. In the summer of 2011, Ryan Jefferis '12 worked on improving the temperature stability of the lasers and Josh Cheng '13 worked on reducing noise in the laser light sensors. Our first cold cloud was produced on September 2, 2011. We published our design and process in a paper that can be found at the following link: Joey Engelbrecht'13 refined the system so that it is stable and hermetically sealed. Jon Smucker '16 measured the temperature of the MOT cloud. Oliver Vischer'16 built a Fabry-Perot interferometer to make careful measurements of the Rubibium spectrum.

Elephant seismic signals - Using data from the Syracuse Zoo, the Elephant Sanctuary in Tennessee and Dzanga Bai in Central African Republic, we have shown that elephants produce interesting seismic signals at the same time they produce acoustic ones. Student Dan Varney '07 and I built a seismic generator to mimic the signals produced by the elephant feet. Student Alex Williamson '05 worked on the time series analysis processing of much of the acoustic and seismic data . Matrika Bhattarai '04 worked on seismic sensors and instrumentation. Jamie DeGregory '03 analyzed the mechanical properties of an elephant foot. Since early 2007, I have been working with members of the Bioacoustics Laboratory at Cornell University to study the effects of seismic exploration on the behavior of elephants in Loango Park, Gabon, Africa. Nik Batruch '08, Peter Wrege (Cornell) and I traveled to Gabon in March 2007 and placed 10 listening posts in the park, which are recording seismic and acoustic signals for 6 months. We analyzed the recordings to develop methods of elephant census via acoustic and seismic signals and to determine the impact of scheduled oil exploration activities. A description of this project was published in the August 2007 H&S Newsletter and can be found at the following link: Another article can be found at:

Electrodynamics with FDTD - The dynamic behavior of electric and magnetic fields can be simulated on a computer using a suitable algorithm. The Yee grid and algorithm has become the de facto standard for these calculations. Maksim Sipos '08 and I have been studying the algorithm and applying it to systems which simulate the fantastic world of invisibility and to microwave filters for low temperature research. This simulation technique is now used in an exercise in our Electrodynamics course and a paper was published in the April/May 2008 issue of the American Journal of Physics.

Stellar occultations by asteroids - We are working with The International Occultation Timing Association group of observers who use occultation timing measurements to determine the size and shape of asteroid shadows on the Earth. This information can be combined with brightness measurements to give some indication of the surface composition. The method can also provide information about the eclipsed star. (See our paper in Publications of the Astronomical Society of the Pacific, December 2006) I have worked on this program with students Tay Yeelin '07, David Whelan '06 and Kris Georgiev '08.

Exhibits and programs for the Sciencenter - I have a continuing interest in what makes a good exhibit for a hands-on science center. There is the goal of having the exhibit be approachable from many different levels and at many different times. Students have worked with me on exhibit and educational projects for the Sciencenter in Ithaca are: Matt Anderson '00 , Bettina Schimansky '01, Michelle Fura '01, Evan Salim '03, Natalie Burek '05, Lia Stelljes '08, Chris Stathis '11.