No mystery what happens to these ‘ghostlike’ atoms
Trapped and frozen atoms at heart of Samir Bali’s research
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Published
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Chanakya Pandya, left, Samir Bali, Andy Zabinski, and Nikolus Miller work in Bali's lab in Kreger Hall. (Scott Kissell photo)
No mystery what happens to these ‘ghostlike’ atoms
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Published
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There is a line Samir Bali often uses when discussing his research. “All good science,” Bali tells his audience, “happens in the dark.”
That certainly fits for one of Bali’s main research topics, as the Miami University Physics professor uses infrared viewers to demonstrate how lasers can trap and freeze atoms in a type of “optical lattice.” This gives the ball of atoms a wispy and ghostlike appearance as they disperse and eventually vanish once the magnetic trap is turned off.
That fits the season, too. Bali compares the atoms’ appearance to that of Casper, the celebrated “friendly ghost,” a particular favorite as the fall season marches toward Halloween.
Viewers are generally amazed when they witness what happens to those frozen atoms once they’re released.
“Casper kind of explodes,” Bali said, “but explodes in slow motion. You can see the atoms leaving, moving at speeds of centimeters per second. They are very slow.”
That certainly fits for one of Bali’s main research topics, as the Miami University Physics professor uses infrared viewers to demonstrate how lasers can trap and freeze atoms in a type of “optical lattice.” This gives the ball of atoms a wispy and ghostlike appearance as they disperse and eventually vanish once the magnetic trap is turned off.
That fits the season, too. Bali compares the atoms’ appearance to that of Casper, the celebrated “friendly ghost,” a particular favorite as the fall season marches toward Halloween.
Viewers are generally amazed when they witness what happens to those frozen atoms once they’re released.
“Casper kind of explodes,” Bali said, “but explodes in slow motion. You can see the atoms leaving, moving at speeds of centimeters per second. They are very slow.”
Samir Bali, left, professor of Physics, works in his lab with student Caden McCollum. (Photo by Scott Kissell)
When the atoms are trapped, it is effectively “the coldest spot in Ohio,” Bali said, where the temperature is a million times colder than that of outer space.
“It’s as close to absolute zero as one could ever get,” Bali said.
Using laser beams shining in different directions, the atoms are trapped in the intersecting regions, slowing the atoms down to the point observers can see them move.
Bali’s other main research area is sensing extremely weak magnetic fields. Bali and Imran Mirza, assistant professor of Physics, recently received an $800,000 grant from the National Science Foundation for a collaboration with the University of Wisconsin, Madison.
The grant, from the NSF’s Expanding Capacity in Quantum Information Science and Engineering (ExpandQISE) program, will also help the researchers expand Quantum Information Science and Engineering (QISE) at Miami by developing new QISE-centered physics courses.
The idea behind that research, Bali said, is to make a “super perfect” beam of light that has significantly less fluctuations than the most stable laser beam ever built or that one could ever hope to build.
”It’s called a squeezed light beam, meaning we squeeze out all the fluctuations from it that we can, even the fluctuations at the quantum level,” Bali said. “All the quantum fluctuations cannot be squeezed out, but we squeeze them out by a factor of 10 or more than the quietest laser beam one could possibly hope to achieve.”
This squeezed light beam is capable of sensing extremely weak magnetic fields, trillions of times weaker than a kitchen magnet, such as those emanated by the human brain, or a fetal heart. The magnetic sensing apparatus, mounted on a drone, may also be used to detect faint magnetic anomalies which reveal the presence of oils, gasses, or minerals in terrains that aren’t easily accessible.
Currently, two master’s students and four undergraduates are assisting Bali and Mirza with this research.
“From a student point of view, there is a lot of cutting-edge technology that one can work with, both commercial as well as instrumentation that we build in-house ourselves,” Bali said.
