At age 10, new matter is certainly growing up
Bose-Einstein condensate celebrates its birthday today
Daily Camera, June 5, 2005
Solids, liquids and gases have been around for billions of years. A fourth form of matter, which announced its arrival in the universe through a monitor in a University of Colorado laboratory, celebrates its 10th birthday today.
A team led by CU professor Carl Wieman and National Institute of Standards and Technology scientist Eric Cornell first coaxed Bose-Einstein condensate into existence on the morning of June 5, 1995. The discovery, which won the pair the 2001 Nobel Prize in physics, simultaneously ended a 70-year scientific quest and launched a new movement in the field of physics of unexpected force and breadth.
"I thought it was going to be a big deal." Cornell, 43, said Wednesday from his office at JILA, the joint CU-NIST institute where both he and Wieman have collaborated since 1990. "I didn't think it was going to be as big a deal as it became."
The number of labs capable of creating Bose-Einstein condensate has blossomed from one to more than 100 worldwide. There are more Bose-Einstein conferences in a given year than he could possibly get to, Cornell said.
The field has attracted a growing number of physicists with increasingly broad interests. Some want to understand high-temperature superconductivity, which allows electricity to flow through wires without resistance. Others want to witness and then manipulate quantum behavior without having to squint at individual atoms . Still others are striving to harness Bose-Einstein condensates to make real-world devices such as ultra-precise measurement and navigation devices.
"Part of what makes the field so vibrant is that it's not just the atomic physicists staring at their own bellybuttons," Cornell said.
Cornell's and Wieman's original Bose-Einstein condensate began as a fog of rubidium atoms, each with its own personality. A complicated process of laser cooling, evaporative cooling and magnetic trapping in a custom-made contraption once described as looking "like under the kitchen sink" allowed all but the most lethargic atoms to escape.
The 2,000 that remained scarcely moved. They hung in a carrot-sized vacuum tube. They chilled at 170 nanokelvin, or billionths of a degree above absolute zero. That's minus-459.7 degrees Fahrenheit, where atomic motion theoretically ceases.
Residual heat from the Big Bang keeps space's coldest spots 18 times warmer.
In a 1998 Scientific American article describing their work, Wieman and Cornell described the temperatures required using a hypothetical coast-to-coast thermometer. If Los Angeles marked 80 degrees, and the Arizona-California border marked the temperature that water freezes, Bose-Einstein wouldn't happen until the mercury was half a millimeter from the thermometer's base at Times Square in New York.
"There were big questions as to whether physics was going to allow us to do it," Wieman said.
But at 10:54 a .m. one decade ago, the universe 's all-time low temperature was in the bottom of a magnetic trap in Boulder. And as predicted by Albert Einstein and Satyendra Nath Bose in 1924, the remaining rubidium atoms lost their individuality and became a single "super- atom " whose quantum waves rippled in sweet unison.
The discovery launched Cornell into scientific stardom and further elevated Wieman's standing as one of the world's top atomic physicists, master of taming atoms with lasers.
"Scientists in Boulder, Colorado, have created a new state of matter," Jay Leno said in a Tonight Show monologue. "It's the first time that has been done since Zima."
In 1997, curators from the Smithsonian Institution collected the apparatus from Lab B224. The parts they carefully numbered included inexpensive diode lasers similar to those found in CD players and cooling coils from McGuckin Hardware.
It had cost $50,000 in hardware, a pittance for groundbreaking experimental physics, a domain of supercolliders and satellites. It was as if gifted mechanics had souped-up a street rod and won at Indy.
"It's not just that the system they discovered was great," said Allan Griffin, a physicist from the University of Toronto and organizer of a 10th-anniversary Bose-Einstein conference in Banff, Alberta, in February. "But the actual experiment they did could be considered as one of the most beautiful experiments in 100 years."
The end was the beginning
Bose-Einstein condensate was a popular area of physics before its discovery, and it has taken off since. Griffin, 66, embodies one of the key factors in the field's growth.
He is a condensed-matter physicist, a theoretician specializing in high-temperature superconductors, discovered in 1986, but still not well-understood.
Understanding the physics of superconductivity requires fine-tuning molecular interactions in a potential superconductor in ways impossible in the solid-liquid-gas world.
But superconductors share quantum properties with fermionic condensates, a variant of Bose-Einstein condensate pioneered by NIST physicist Deborah Jin in her JILA lab in 2003. Fermionic condensates - now one of the hottest fields in the study of ultracold matter - create not "superatoms," but rather "supermolecules."
They could allow scientists to change molecular relationships with the turn of a knob.
" A lot of us have switched our research area to this topic," Griffin said. "It's opened up a whole new world."
David Pritchard, an atomic-physics pioneer and professor at the Massachusetts Institute of Technology, views Bose-Einstein condensate as a turning point in his field.
Pritchard was Cornell's Ph.D. advisor and a mentor to Wieman, who as an MIT undergraduate was a crew member on Pritchard's 30-foot sloop. Pritchard also brought to MIT Wolfgang Ketterle, who shared the Nobel Prize with the CU team for his creation of a Bose-Einstein condensate from sodium atoms four months after the CU success.
Before Bose-Einstein, atomic physicists had reached a point where they had total control of individual atoms . If they went any smaller, they'd be delving into nuclear physics, Pritchard said. Instead, atomic physicists are thinking big, creating condensates and manipulating them.
Even as research in pure Bose-Einstein condensates themselves tapers off, work involving condensates as a tool in other research is blossoming.
Cornell's current work includes an effort to nudge a condensate to within a few millionths of a meter of its glass container, which is at room temperature. The extreme temperature difference - a factor of 10 billion - leads to the glass acting like a magnet. Cornell wants to understand what makes the glass do that. The condensate becomes a tool to that end.
"I love that," Cornell said. "When lasers were first invented, people spent a lot of time studying lasers. And there are still people who study lasers, but most use them for something else."
The partnership lives on
Bose-Einstein condensate changed the lives of its creators in different ways. For Cornell, things were different immediately.
"I went from being an assistant professor working in cold atoms to being Mr. BEC and giving keynote addresses," Cornell said.
Wieman said the Nobel Prize was his life-changing event. He has become a leading voice in improving science education, spending about 60 percent of his time on his Physics Education Technology Project, which creates free online simulations for use in classrooms. In 2004 he was named U.S. Professor of the Year.
Demands on their time and evolving interests mean they work together less now. But the eminent researchers still cooperate closely enough that Wieman calls theirs a relationship that is "certainly unique in physics and very well could be unique in all of science, if you look at the length of time we've successfully and happily collaborated."
They remain close friends, as evinced by the many hours Wieman spent with Cornell and his family late last year, when his collaborator was gravely ill with necrotizing fasciitis. The tissue-destroying disease took Cornell's left arm and shoulder and nearly his life.
Cornell is back working nearly full time. In his JILA Tower office Wednesday, he demonstrated how a new prosthetic arm could hold a clipboard - useful during lectures - and an H-P 15c calculator he has had since grad school.
Also in his office were a softball and a right-handed glove. He uses it to practice catching and throwing with the same hand. On Monday, he finished the Bolder Boulder 10K road race in 2:00:24.
In the lab, their Bose-Einstein work has diverged. Cornell is working on a Bose-Einstein condensate-based interferometer, which could detect subtle changes in gravity and acceleration in navigation.
"It's not commercialized, but it's work with a very applied goal in mind," Cornell said.
Wieman's Bose-Einstein condensate research focuses on greater control of the interaction of matter. It's new enough that it still lacks a name.
"It's exploring new kinds of chemistry - of actually transforming atoms into molecules," he said. "And so you don't know where it's going to go."
© 2008 Todd Neff