Why the age of quantum computing is nearer than you think

But recent advances suggest that the inception of such a computer is closer than many have thought. This was the crux of a recent New York Times article that detailed new improvements IBM has made in honing quantum computing – specifically, IBM researchers sped up computation and increased the lifetime of certain qubits, which tend to be unstable. It's usually a good sign for an emerging technology when the in-house applied research arm of a major tech company, which tend to invest their time and resources very conservatively, conveys optimism about its application.

The MPQ team has developed perhaps one of the most distilled and versatile permutations of of this technology. It implements two lone rubidium atoms as the nodes of the network. The qubit of information, stored as the quantum state of the one of the atoms, can be transfered through an emitted photon – which carries the quantum information  –  and is absorbed by the other rubidium atom. Over the winding fiber-optic cable, information is transmitted, received, and stored. The process is also completely reversible.

Send, read, write, save. The essential functions of networked computing can now be demonstrated in a system of just two atoms.

To heighten the chances of interaction between the photons and the rubidium atoms, which normally almost never occurs, the physicists designed "optical cavities," mirror-lined pockets that direct and then continually redirect the photon through the rubidium.

The experiment also demonstrates the possibility of something particularly brow-raising in the field of quantum computing: entanglement. Quantum entanglement occurs when particles interact physically, correlate their quantum states, and are then separated. The result is that a manipulation or measurement (which at the quantum scale are the same thing) of one quantum state affects the other. Hence they are "entangled." For example, measuring the spin as clockwise in particle A will spontaneously render the spin of particle B counterclockwise, regardless of whether particle B is six feet, six miles, or six light-years away. The distance separating the two does not matter. If you find this disconcerting, you're in good company. Albert Einstein, who could never quite accept the capricious nature of quantum physics, once decried this phenomenon as "Spukhafte Fernwirkung" or "spooky action at a distance."

It is impossible to predict the many implications of a viable quantum computer composed of a few hundred qubits, let alone the possibilities of technology derived from quantum entanglement – a concept about which many physicists are still puzzled. The MPQ team has openly acknowledged that this prototype can be improved markedly (their current success rate for transferring the quantum states is 0.2 percent). But consider the progress it marks since 1982, when quantum computing was a mere idea, and most definitely not an elegant experiment running the distance between two German labs.

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