New Quantum Entanglement Experiment Successful

"We've entangled something that has never been entangled before, and it's the kind of physical, oscillating system you see in the classical world, just much smaller," said John Jost, a physics graduate student at the University of Colorado at Boulder, and a guest researcher at the National Institute of Standards and Technology. Jost and team describe their findings in the June 4 issue of the journal Nature.(...)

To achieve this feat of entanglement, Jost and colleagues set up two pairs of ions (atoms with one electron removed, so that they have a positive charge). Each pair included one beryllium and one magnesium ion, vibrating back and forth toward and away from each other as if they were connected by an invisible spring.

Using electric fields and lasers, the researchers herded the ions into separate pairs and then entangled their motion. Then they separated the pairs by 240 micrometers (millionths of a meter), which is actually quite a span for an atom. Even at this distance, when the researchers changed the motion of one pair — stopped or started the vibrations — the other responded immediately, stopping or starting in kind.