It's got two fixed, entangled atoms as network nodes and the means of transmitting data is a single, controllable photon, say researchers at the Max Planck Institute of Quantum Optics.

Scientists at the Quantum Dynamics division of the Max Planck Institute of Quantum Optics (MPQ) in Garching, Germany announced Wednesday that they have built the very first, elementary quantum network comprised of a pair of entangled atoms that transmit information to each other via single photons.

That and a couple of bucks will get you a cup of coffee, plus anything from a perfectly secure data exchange system to the massive scaling via distributed processing of the already mind-bogglingly powerful, if theoretical, potential of a standalone quantum computer.

These are indeed heady days for the pioneers of quantum computing, with each news cycle seemingly bringing forth a major breakthrough in a subatomic frontier that appears poised to revolutionize how our calculating machines deliver us everything from satellite mapping to LOLcats.

It's also a daunting time for those of us who have barely just sussed out the mechanics of old-fashioned, silicon-based computer chipsonly to be confronted with this new science of computing, a full understanding of which requires one to be not just an advanced electrical engineer, but a quantum physicist to boot.

All of which is to say that, yes, the bright individuals who are trying to harness the computational power of stuff so small and weird, it can only be described mathematically, are at it again.

Years in the Making

The accomplishment was the result of years of work, according to Scientific Computing. Lead researcher Prof. Gerhard Rempe and his colleagues had to figure out a means of exercising "perfect control" over all the components in their quantum network, which first meant getting the two atoms that make up the network's receptor nodes to somehow stay stationary, because a couple of free-floating atoms wouldn't be able to communicate with the photons relaying information between the two very efficiently.

"This approach to quantum networking is particularly promising because it provides a clear perspective for scalability," Rempe told the journal. His colleague and leader of the experiment, Dr. Stephan Ritter, added, "We were able to prove that the quantum states can be transferred much better than possible with any classical network."

The team was able to fix their atoms in optical cavities, basically a couple of highly reflective mirrors a short distance from each other, by means of fine-tuned laser beams. Why mirrors? Photons entering the cavity bounce around the mirrors "several thousand times," which actually enhances the atom-photon interaction and enables the network node atoms to absorb the photon-based data packets "coherently and with high efficiency," according to the scientists.

The use of optical cavities for a quantum network was proposed by Prof. Ignacio Cirac, an MPQ directory and head of its Theory division.

"In fact, we demonstrate the feasibility of the theoretical approach developed by Prof. Cirac," Ritter said.

After trapping and stabilizing the atoms that would serve as the system's network nodes, the scientists had to get the atoms to emit single photons encoded with information in a controlled way and transfer that information onto a second photon.

Then, to demonstrate an actual networking effect, the team connected two such systems "and quantum information was exchanged between them with high efficiency and fidelity," Scientific Computing reported.

The two systems were connected by a roughly 180-foot-long fiber optic cable and hosted in separate labs about 60 feet apart from each other. So basically, walking down the hall and just telling the guys in the other lab what was on the photon would have been about as effective, but the point of the exercise was to show the network performing as designed and to worry about scaling it out to purposefulness later.

Weird and Weirder Science

Quantum networking is the practical application of experimental quantum cryptography, like the "blind quantum computing" demonstration by another team of researchers at the University of Vienna's Center for Quantum Science and Technology earlier this year, which involved transmitting an algorithm to acomputer, running it, and receiving it back without the computer's operator being able to snoop on those operations.

Like its cousin, quantum computing, quantum networking takes advantage of the fact that subatomic particles of matter can exist in multiple statessuch as "on" and "off" to reference the binary process by which digital computing operatesat the same time.

Again, this is exceedingly difficult stuff to wrap one's head around, but suffice to say that these properties enable the quantum bits, or qubits, that power quantum computers and the single-photon data packets developed for the MPQ team's quantum network to perform their duties much more powerfully and securely than the non-quantum parts used in currently available PC chips and network infrastructure devices.

Of course, all of this is still very much in the realm of conjecture. Quantum computing is still highly theoretical, with demonstrations like the MPQ team's limited to laboratory settings. There are no practical quantum computers,just experimental ones.

For one thing, scientists have yet to actually scale out their quantum computers and quantum networks to the point that they can actually out-perform their digital counterparts. For another, the cost of doing so appears to be, for the time being anyway, prohibitive.

But clearly, a boffin poking around in the subatomic, algorithmic ether can dare to dream.