Dance for me, little atom!

Do they wear dancing costumes?

Reuters reports that NIST has developed what may someday become a building block for quantum computing.

Suspended in laser light, thousands of atoms pair up and dance, each moving in perfect counterpoint to its partner. Porto’s team isolated pairs of atoms in a lattice of light formed by six laser beams all fixed on one point, suspending the atoms in a uniform pattern. "There is no container. It is levitated by the laser beams."

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Cleaning up grubby nanotubes

Researchers at NIST have developed a simpler method to "clean" carbon nanotube structures using an excimer laser.

In a forthcoming issue of Chemical Physics Letters, the NIST/NREL team describes how pulses from an excimer laser greatly reduce the amount of carbon impurities in a sample of bulk carbon single-walled nanotubes, without destroying tubes. Both visual examination and quantitative measurements of material structure and composition verify that the resulting sample is "cleaner". The exact cleaning process may need to be slightly modified depending on how the nanotubes are made, the authors note. But the general approach is simpler and less costly than conventional "wet chemistry" processes, which can damage the tubes and also require removal of solvents afterwards.

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Identifying defects using laser lattices

NIST researchers have come up with a new method that may help to identify defects in superconductors, using a lattice of laser beams controlling a Bose-Einstein condensate.

The JILA experiments were performed with 3 million rubidium atoms held in a magnetic trap. A superfluid of vortices was created by spinning the trap. The reddish BEC cloud, about 100 micrometers in diameter, contained about 100 hollow vortices, like a spinning bundle of fibers. Lasers were used to set up optical lattices grids of light in an arrangement of energy peaks and troughs in triangular and square patterns and focus them onto the BEC.

Because BECs and optical lattices can be precisely controlled, the technique may be useful in studying more mysterious patterned superfluids, such as superconductors.

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