19:00 18 November 2010 by Kate McAlpine
The first supersolid – a ghostly, quantum form of matter in which a solid flows, frictionless, through itself – was reportedly made in 2004. But a debate has raged ever since over whether the researchers involved had simply misinterpreted their results. Now two new studies suggest that genuine supersolids have been made after all.
According to quantum theory, supersolidity should kick in at very low temperatures. In a solid, atoms are bound together in a regular lattice, keeping their structure rigid under normal circumstances. But if you cool some solids close to absolute zero, they should become frictionless, flowing supersolids, while retaining their lattice structure.
In the original experiment, Eunseong Kim – now of the Korea Advanced Institute of Science and Technology in Daejeon, South Korea – and Moses Chan of Pennsylvania State University in University Park cooled and pressurised liquid helium until the atoms were forced into a crystal lattice.
They then made a cylinder filled with this solid helium spin one way and then the other, over and over again. As they cooled it, the cylinder switched direction more frequently.
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http://www.newscientist.com/article/dn19748-new-evidence-that-weird-quantum-supersolid-exists.html