Heating Up Quantum Science Education With Laser Cooling
If you imagine a laser, you might think of beams of light popping balloons or slicing through a metal slab like butter. Lasers can indeed heat things up, but they can also cool things down.
These days, physicists use laser cooling to understand the fundamentals of quantum physics, with implications for building things like super-precise atomic clocks and super-fast quantum computers. To study the quantum properties of atoms—how they behave when classical, temperature-based influences are stripped away—you need to chill them to as close to absolute zero as you can. This is where the lasers come in.
As Claire Warner, a graduate student in Sebastian Will’s lab at Columbia, recently explained to a group of teachers from across the United States, photons, the energy packets that make up light, have momentum when fired from a laser. When those photons hit an atom, that atom gets a "momentum kick" that slows it down. In just three milliseconds, atoms can be super-cooled to just above absolute zero, -459.67 °F. Quantum physics then takes over, and it’s off to the experimental races.
“Laser Cooling: Quantum Physics Applications for High School Students,” is the most recent workshop in a series that Will’s lab is developing with the nonprofit STEMteachersNYC. Funded by Will’s National Science Foundation CAREER award, the Quantum Physics Outreach Program (QPOP) is giving high school teachers the tools to share quantum physics with their students.
"It's providing teachers with simple concepts that allow them to make a connection to modern quantum technology,” Will said. In collaboration with Fernand Brunschwig at STEMteachersNYC, Will and his graduate students distill their work in experimental physics to a few simple ideas that the teachers attending the workshops can understand. The training has a multiplier effect for reaching new audiences: if 50 teachers who attend a workshop go on to teach these concepts to 30 students at a time, that’s now 1,500 students with new quantum knowledge, Will said.
Often, high school students have already covered the basics—atomic energy levels, force and momentum, waves and the Doppler effect, and so on—just not necessarily in the context of quantum physics. Once equipped, teachers can take their students from performing calculations with hypothetical cannonballs to calculations about laser cooling, a real-world physics application. “The conceptual leaps that need to be made aren’t that big,” Warner said.
Warner is now an expert on laser cooling, but wasn’t always. Popular science tends to focus on outer space or black holes, and although the basics of quantum physics have been around for nearly a century, most high school classrooms still focus on classical Newtonian physics. “There aren’t PBS specials on quantum physics and its modern applications,” she said. She learned about ultracold atoms in a physics lab as an undergraduate; she hopes the workshops might introduce students to quantum science even earlier in their academic careers.
Developing the workshops has been challenging, said Warner. In speaking to other researchers, a few technical words can convey what you mean. That’s not the case when translating to a room of high school teachers. “You can’t use jargon or acronyms,” she said. “You really have to go back to basics." Will said that he and his students, with STEMteachersNYC, are continuously improving the workshops as they move forward.
“The public image of quantum is, ‘Oh my, I can’t possibly understand this. It’s too weird,’” Brunschwig said. But the quantum world is all around us, he noted, one that he hopes the workshop series will help to demystify.