Friday July 23, 01:00 PM By Maggie McKee The strongest evidence yet for a long sought after form of matter in which particles that normally abhor each other pair up and flow together has been shown by Austrian researchers. The feat - which is being hotly pursued by at least six other groups - may lend insight into the nature of neutron stars and the creation of room-temperature superconductors. Over the last decade, physicists working with extremely cold gases have created nine different frictionless "superfluids" with bosons, elementary particles with integer spins (1, 2, etc.). In a superfluid, particles do not lose energy when they flow, for example, by heat due to friction. But creating a superfluid made of subatomic particles called fermions, which include protons, neutrons and electrons and have half-integer spins (1/2, 3/2, etc.), initially seemed impossible. That is because a quantum mechanical law prevents identical fermions from sharing the same state of being. For example, having the same location or momentum - conditions required for superfluidity. But recently physicists have discovered that fermions can be coaxed to pair up, so that their spins add together for a split second, so the pair behaves like a boson. "At first, fermions were considered boring" compared to bosons, says Rudolf Grimm, a physicist at Innsbruck University in Austria and an author of one of the new studies published in this week's Science . "Now that we have learned they can pair up, we have learned the physics of fermions is even more interesting." Radio waves The first evidence for physicists putting loosely linked paired fermions together in the same quantum state came in December 2003, and in the months since, they have been experimenting with the properties of the new form of matter. Now, Grimm and his colleagues believe they have created a superfluid of fermions based on their studies of an ultra-cooled gas of lithium atoms. The researchers tweaked the temperature and density of the gas and blasted it with radio waves. The radio waves can break apart pairs of lithium atoms, so the team determined the number of pairs and the strength of their bonds by which radio wavelengths the gas absorbed. As they lowered the temperature to just ten-millionths of a degree above absolute zero, the researchers saw the gap in the spectrum between paired and unpaired electrons grow to the point expected for a superfluid. Fledgling field He says this and a couple of other recent studies, using different techniques, all point to the creation of superfluids. "The next big step is to observe the superfluidity directly," he told New Scientist . That will come by rotating the gas and observing vortices peculiar to the fluids - something that is "not at all easy to do," he says. His study sheds light on the fledgling field, he says: "We have for the first time measured the properties of these pairs. That gives us a key to compare observations with theory." "We saw quite convincingly that in the lowest temperatures achieved in the experiment, [Grimm and his team] are in the superfluid regime," Paivi Torma at the University of Jyvaskyla in Finland, who wrote a paper supporting Grimm's work, told New Scientist . Journal references: Science (10.1126/science.1100818 and 10.1126/science.1100782) Related Stories from New Scientist: New form of matter created in lab