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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More Teleportation?

It won’t be coming any sooner than the last time I mentioned researchers teleporting atoms but researchers in Australia have proposed a way to teleport atoms from one location to another.

The full paper is available here as well as an animated description here.

What differentiates our scheme from what is usually termed quantum teleportation is that our scheme does not require the sender and receiver to share entangled states, as there is no measurement step involved in sending the information.

In this scheme the sender and receiver require a reservoir of extremely cold atoms, known as a Bose-Einstein condensate (BEC).

BEC is a state of matter that occurs when atoms become very cold, (about 100 billionths of a degree about absolute zero).

Due to a phenomenon known as Bose-Enhancement, all the atoms like to act the same way. This causes the atoms to act as one macroscopic matterwave, rather than a collection of individual atoms.

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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Quantum bits with molecules reports that researchers at the Max Planck Institute have developed a novel method of trapping molecules in a lattice of overlapping laser beams and keeping them there.

The work was achieved by physicists at the Max Planck Institute of Quantum Optics in Garching, and the resulting shape of the optical lattice resembles a stack of egg cartons, with exactly two atoms placed into the each well of the carton. By applying a magnetic field, these atom pairs are associated to molecules. The work is reported in the Sept. 24 edition of the journal Nature Physics.

Researchers created the optical lattice by intersecting several laser beams and transferred a very cold gas of rubidium atoms, also called a Bose-Einstein condensate, into the lattice.
The laser lattice looks like a stack of egg cartons with the wells representing locations where the rubidium atoms tend to settle.

The depth of the lattice sites depends on laser intensity. At low laser
intensities, the atoms can move almost freely in the optical lattice
and move from site to site. With increasing laser intensities, the
wells become deeper and deeper and at some point the atoms cannot
escape from the well in which they find themselves — they are trapped
and localized. The resulting highly ordered state is called a Mott
insulator state. Changing the overall atom number in the lattice, the
physicists were able to create a situation with exactly two atoms per
site in the center of the lattice.

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