New supergas debuts

When particles of matter cooperate with each other, the result can be something super. For instance, there’s superconductivity, in which coordinated pairs of electrons flow resistancefree through a solid, and there’s superfluidity, in which atoms or molecules flow without friction.

ALL ABOARD! Rising peak (back to front) shows an increasing fraction of potassium atoms piling into a new state of matter as a magnetic field reaches a specific strength. NIST–University of Colorado

Now, Deborah S. Jin and her colleagues at JILA, a Boulder, Colo.–based joint research operation of the National Institute of Standards and Technology and the University of Colorado, have conjured up a muscular new super state of matter.

This first example of the new super stuff is a gas of some half-million potassium atoms chilled below 50 nanokelvins and influenced by a magnetic field. Jin, Cindy A. Regal, and Markus Greiner describe the novel substance, dubbed a fermionic condensate, in the Jan. 30 Physical Review Letters.

The new state of matter is reminiscent of a Bose-Einstein condensate (BEC), a type of superfluid in which an ultracold cloud of atoms or molecules coalesces into a single quantum state (SN: 11/22/03, p.324: Quantum Pileup: Ultracold molecules meld into oneness). Yet the new material isn’t a BEC, notes Eric A. Cornell, a BEC pioneer also of JILA.

That’s because the potassium atoms in the new material coordinate with each other in pair-wise fashion not found in BECs but similar to what takes place between the electrons of a superconductor. On the other hand, Cornell notes, the pairing in the potassium gas is far stronger than that in any superconductor ever observed. The new substance is “neither fish nor fowl,” he says.

The extraordinary strength of pairing makes this first-ever fermionic condensate of special interest to scientists and engineers because it’s a property that scientists expect to find in future superconductors that might operate at room temperature. This new work may provide clues for how to attain that long-sought goal, Jin says.

More Stories from Science News on Physics