Previously, physicists have shown that they could use teleportation to transfer information from one photon to another or between nearby atoms. In the new research, the scientists used light to transfer quantum information between two well-separated atoms.

“It’s that hybrid approach that we’ve demonstrated that looks to be an interesting way to proceed,” said Christopher Monroe, a University of Maryland physicist and the senior author of a paper describing the research in the Jan. 23 issue of the journal Science.

Present-day digital computers store information as zeroes and ones. In a future quantum computer, a single bit of information could be both zero and one at the same time. (In essence, a quantum coin toss would be both heads and tails until someone actually looked at the coin, at which time the coin instantly becomes one or the other.) In theory, a quantum computer could calculate certain types of problems much more quickly than digital computers.

In the experiment, two ytterbium ions, cooled to a fraction of a degree above absolute zero, served as the two quantum coins. A microwave pulse wrote quantum information onto one; a second microwave pulse placed the ion into a state of equal probabilities of heads and tails.

A laser then induced each ion to emit exactly one photon, collected by a lens and guided through fiber optics to a beam splitter that could reflect the photons or let them pass through. Two detectors then captured and recorded the photons. Because it was not known which photon came from which atom, the photons became “entangled,” meaning that the behavior of the two particles became wrapped up in a single equation even though they were not in the same place. And, oddly, because the photons were emitted by the ions, the two ions also became entangled.