Thursday, August 30, 2012

A one-way street for spinning atoms

A one-way street for spinning atoms: In previous experiments, the RLE researchers created a superfluid — a completely frictionless gas — of lithium atoms. In their new experiment, the researchers used laser beams to trap a cloud of lithium atoms about 50 micrometers in diameter. The atoms were cooled to just a few billionths of a degree above absolute zero...

The researchers illuminated the gas with a pair of laser beams, sorting the atoms into two lanes, each of which consists of atoms with the same spin moving in the same direction. For the first time in an atomic system, this correlation of atoms’ spins with their velocities was directly measured.

“The combined system of ultracold atoms and the light we shine on them forms a material with unique properties,” says Lawrence Cheuk, lead author of the paper and a graduate student in MIT’s physics department. “The gas acts as a quantum diode, a device that regulates the flow of spin currents.”

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