College of Arts & Science at Miami University
The Coldest Matter in the Universe
Conducting Research in a Physics Lab
(with Dr. Samir Bali, April 2009)
A full text transcript of the video is available below.
(This video shows students conducting research in the Bali lab. This research has garnered national attention for Dr. Bali and his students.)
Hello. I'm Samir Bali, an Associate Professor of Physics at Miami University. I teach courses in freshmen, introductory physics, a senior-level course in lasers, and also a graduate-level advanced electromagnetism course.
I have 7 undergraduates and 1 graduate student working with me in my research lab. We conduct research on atoms that have been cooled and, therefore, slowed down and ultimately trapped by laser beams.
These atoms are so cold, a millionth of a degree above absolute zero ... that means a million times colder than even liquid helium. They're so cold that you can actually see them move with your bare eyes. They are the coldest matter in the universe.
How does this work? You may think of an oncoming atom as a bowling ball which you are trying to stop by firing at in the opposite direction laser photons ... which are like ping pong balls. If you have enough ping pong balls and, keep in mind that a laser that puts out even just a fraction of a milliwatt ... too weak to hurt your eye if it were to hit your eye ... even that laser puts out a million times a billion photons per second. There are enough ping pong balls to slow that bowling ball, that atom to nearly a standstill. Slowing down the movement of atoms allows us to better manipulate their behavior.
This research contributes to 2 exciting new technologies. Nanolithography is one, which is literally writing with atoms, and allows us to store huge amounts of data on incredibly small devices. You could hold the entire Library of Congress in the palm of your hand! The other technology is quantum computing which enables us to compute millions of times faster than the fastest current computers.
Cold atom experiments are extraordinarily sensitive. Mechanical vibrations, such as from a truck passing by outside, can destabilize the lasers. So, while taking data, we need to "float" the experimental chamber on a layer of air. Stray magnetic fields, including the Earth's magnetic field, need to be completely cancelled. The experiments themselves need to be done in ultra-high vacuum [chambers], which were assembled by students at Miami. Barely touching the inside of the ultra-high vacuum chamber introduces enough body oil to completely ruin the experiment.
As you might guess, almost all of the instruments we need are not commercially available. So we build them ourselves. My undergraduate and graduate students build state-of-the-art laser systems and sophisticated electronic and magnetic control systems for the experiments.
If you like building things and conducting cool — micro-Kelvin cool — cutting edge research, then come to Miami and visit my lab.
- Dr. Samir Bali