Eric Cornell and His Cool Condensate

In preparation for Sigma Pi Sigma’s 2016 Quadrennial Physics Congress (PhysCon), Kaufman sat down to talk with Nobel laureate Eric Cornell about his pioneering work in condensed-matter physics. She also delved into progress made on supersymmetry and string theory by S. James Gates, distinguished professor and Center for String & Particle Theory director at the University of Maryland. Cornell and Gates will be keynote speakers at PhysCon, which we cordially invite you to attend!

What happens when things get cold? Not just scarf-and-mittens chilly or even midnight-in-Antarctica cold—but really, really cold?

Answering that question earned Eric Allin Cornell a Nobel Prize.

He, along with Carl Wieman, synthesized in 1995 the first Bose–Einstein condensate using a process that cools matter to temperatures that seem impossibly low. Even the deep vacuum of space is far too warm for Bose–Einstein condensate (BEC). Only if you can get to about 170 nK—about 0.00000017 degrees above absolute zero—do some weird things start happening.

Born in Palo Alto in 1961, Cornell grew up in Cambridge, Massachusetts, where he was “an all-around curious kid,” he told Sigma Pi Sigma, reading books surreptitiously during class and pondering physics brainteasers at night.

As an undergrad at Stanford University, Cornell majored in physics, “but I wasn’t necessarily gelled there,” he told Sigma Pi Sigma. “I thought I would pursue something more on the humanities or social sciences side.”

Ultimately, it was a job during the summers and after school that tipped the scales, as well as a year in Asia.

Cornell had taken a year off from college to study Chinese and teach English in Taiwan. He returned from that experience realizing that physics was something he enjoyed and was good at. He had been spending afternoons and summers working with the low-temperature physics groups to earn money. “The [physics] classes were OK,” Cornell says. “It was really the after-school and summer thing that I found so thrilling. That was, I would say, really the thing that made me think I wanted to go and do physics.”

After grad school at the Massachusetts Institute of Technology, he moved to a postdoc position at JILA, a joint institute of NIST and the University of Colorado Boulder. There his experience and interest in low-temperature physics led him to the discovery that won him his Nobel Prize.

“During those early years in Boulder, I spent a lot of time trying to imagine what a Bose–Einstein condensate would be like, if we could ever make one,” he wrote. After his postdoc ended, he stayed at JILA to work on creating a condensate.

BEC is essentially a new form of matter, predicted by Satyendra Nath Bose and Albert Einstein in 1924 to occur when atoms are cooled to almost absolute zero. Physicists had been struggling to create BEC ever since to confirm Bose and Einstein’s theory.

In 1992, when Cornell joined JILA as a professor, “the idea of BEC was in the air,” Cornell once wrote. But the most advanced cooling techniques of the time were not powerful enough to reach the required temperatures.

“We were pretty optimistic in the face of a lot of skepticism,” he told Sigma Pi Sigma. “We had some good arguments for why it would work.”

Creating BEC at JILA required using laser and magnetic traps to bring a cluster of rubidium atoms close to absolute zero. Even 10 millionths of a degree above absolute zero is too warm to create BEC, so getting the substance cold enough took some doing.

Inspired by his advisor-then-supervisor Carl Wieman, Cornell tinkered with equipment using off-the-shelf parts ripped from fax machines and CD drives. “It was the fastest way,” he said. “If you could put something together really fast like that, why bother to order some exotic thing that might or might not work?”

Speed was an important consideration. By the mid-1990s, skepticism in the scientific community had given way to excitement; Cornell says he was less worried about not succeeding and more worried “that people were going to beat us to the punch.”

But in 1995, Cornell, Wieman, and the JILA team first created and observed BEC. Doing so not only confirmed a 71-year-old theory, but also opened up a new branch of physics.

“As things get colder, their quantum mechanical nature tends to get more pronounced,” Cornell said. “They get wavier and wavier and less like particles. The waves of one atom overlap with another atom and form a giant superwave, like a giant, Reagan-esque pompadour.”

Hair metaphors aside, BEC is a way for physicists to observe quantum phenomena on, as Wieman has said, “an almost human scale.” The BEC behaves like one giant atom.
For this discovery, Cornell and Wieman shared the 2001 Nobel Prize, along with Wolfgang Ketterle, whose team at MIT created BEC a few months after the JILA team.

Further reading:

Check out Cornell’s biography at the Nobel Prize site: http://www.nobelprize.org/nobel_prizes/physics/laureates/2001/cornell-bi...

Read the lecture he gave upon receiving his Nobel Prize: http://www.nobelprize.org/nobel_prizes/physics/laureates/2001/cornellwie...

About the Author

Rachel Kaufman is a freelance writer and editor based in Washington, DC. Her work, on science, arts, business, food, health, and more, has been published in the Washington Post, National Geographic News, Smithsonian Magazine, Scientific American, and many other magazines, newspapers, and websites. She tweets infrequently at @rkaufman.