Cold, hard facts of physics

illustration of Samir Bali and researchers using equipment
Cold, hard facts of physics

Researchers explore the mysteries of
quantum physics with ultracold matter

On a series of floating tables in physics professor Samir Bali’s lab, you’ll find a complex matrix of lenses, mirrors, and fibers. But the real magic is what you can’t see.

Such is the nature of working with atoms and infrared laser beams, neither of which can be seen with the naked eye. Bali and his student researchers are exploring the properties of ultracold rubidium atoms – some of the coldest matter in the universe.

When atoms get cold, they move slowly, which makes them easier to observe when magnified. Light from the lasers is used to trap the cold atoms in an optical lattice. Think of an optical lattice like a Rubik’s cube with atoms in many, but not all, of the corners. Once trapped in the lattice, the atoms cool to about 10 millionths of a degree above absolute zero. By adjusting the frequencies, polarization, and laser intensities, the team can see how the atoms behave in various conditions.

Revel in the mystery

Getting undergraduates involved in the research early is critical not only for the advancement of Bali’s projects, but for the development of his students. Graduate and doctoral level physics programs want to see that a student researcher can take the lead and solve problems. Any day in the lab can be a confounding roadblock or an exhilarating breakthrough.

For Bali, this is exactly what makes the pursuit of knowledge so awe-inspiring. He still vividly recalls the sights and sounds of the first physics lab he set foot in at the age of 19, from the red, green and orange lasers to the quiet humming of vacuum pumps.

“I remember feeling this powerful sense of intrigue,” he said. “All I wanted was to not be left out of this deep, never-ending adventure to find out what makes the universe tick.”

He enjoys re-creating those moments by reliving them with his students.

Approximate temperatures

-459 F Rubidium atoms
-166 F Cryotherapy chamber
18 F Oxford, OH ave. low in January
24 F Goggin Ice Arena surface
98.6 F Healthy human