Thursday, December 22, 2011

Crystal Effects at Absolute Zero

Crystals have loomed large in extreme physics this year.

Crystals have been implicated in the “faster than light” performance of CERN neutrinos. As the tiny particles passed through mountains on their way from Switzerland to Italy, they went “faster” than they would have in empty space, possibly the result of the crystals they passed through.

Separately, crystal effects are being used to cool atoms to absolute zero. A crystalline lattice created by lasers is used to bump out the warmest atoms, leaving just the coolest ones behind. This technique cools the atoms to about one billionth of a kelvin, or about as close to absolute zero as has ever been observed.

The resulting arrangement of atoms has not been formally designated as a crystal, but it probably is a crystal, based on the way physicists are describing it. Crystals are important because of the way they distort spacetime, producing coherent arrangements of energy. The coherent light of a laser beam is the best known example of this, but as more specific examples are discovered and studied, physicists may come to a more general understanding of the effect.