The group, led by Carl Wieman of the University of Colorado at Boulder and Eric Cornell of the National Institute of Standards and Technology, says the material, a collection of atoms, behaves like a single "superatom."
The latest work involved tuning the interactions between the atoms to make them attractive or repulsive by exposing them to magnetic fields, Wieman said. The group cooled the matter to just 3 billionths of a degree above absolute zero, the lowest temperature ever achieved.
By then fiddling with the magnetic fields, the researchers shrunk the condensate and forced a tiny explosion, which they say resembles a supernova, albeit in a microscopic level.
The team has dubbed the explosion a bosenova.
"We have gotten down to the nitty-gritty science and have been able to study the behavior of a new material by manipulating it in new and different ways," Wieman said. But he added that several effects of the explosion were inexplicable.
The condensate first shrunk into small clumps as expected, but rather than gradually clumping together in a mass, a sudden explosion sent hundreds of atoms rushing outward. The explosion led to an outward moving shell or jets of material, much like an exploding star.
The explosion corresponds to a tiny amount of energy and continues for a few thousandths of a second, the researchers report. A small chilly remnant of the condensate is left behind, surrounded by the expanding gas.
About half the original atoms mysteriously vanished.
"The 'missing' atoms are almost certainly still around in some form, but just not in a form that we can detect them in our current experiment," Wieman told SPACE.com. "The two likely possibilities are that they have formed into molecules of two rubidium atoms stuck together, or they have gotten enough energy from somewhere to fly away fast enough that they are out of our observation region before we look for them."
He said there are possible atomic physics mechanisms that would release a
lot less energy than observed, or a lot more, "but nothing that matches what we are seeing." The likely answer, he said, is that there is an as-yet undiscovered process that releases energy and involves interactions of atoms at these extremely low temperatures.
"The theoretical calculations of what would happen in this situation predict behaviors that are totally unlike what we've observed," Wieman says, "so the basic process responsible for the bosenova must be something new and different from what has been proposed."
The bosenova explosion is on such a small and cold scale that Wieman rules it out as a potential energy source.
"The amounts of energy involved in all this stuff we see is infinitesimally small compared to any normal scale, so it could never be usefully harnessed," he said. "For example, the amount of energy contained in the motion of one room-temperature gas atom moving in the air is about 100,000 times larger than the total energy contained in the entire bosenova explosion that we see."
The Bose-Einstein condensate is named after Albert Einstein and Indian physicist Satyendra Bose, who predicted its existence in 1924. A paper on the new work appears in the July 19 issue of the journal Nature, and Wieman first discussed it in March at a meeting of the American Physical Society.
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