Entangled photons on a chip could lead to super-fast computers

Photon entanglement on a ring resonator

Photon entanglement is one of the odder properties of quantum physics, but it promises a lot for computing -- if one photon can instantly affect another no matter how far away it is, you could make super-speedy computers and communications that aren't easily limited by physical distances. It hasn't been easy to get entanglement tech down to a manageable size, however, and that's where Italy's Università degli Studi di Pavia might just come to the rescue. Its researchers have developed a tiny emitter that could pump out entangled photons as part of an otherwise ordinary silicon chip. The device, which uses a ring shape to both rope in and emit light, measures just 20 microns across. That's hundreds of times smaller than existing devices, which are comparatively gigantic at a few millimeters wide.

You probably won't see whole processors built around this technique, at least not for a while. Chip makers usually work on the nanometer scale -- Intel's new 14nm processors are far more intricate than this ring. Moreover, there's some refinement left to make sure this part produces a reliable stream of tangled photons. If everything falls into place, however, you could see entanglement rings boosting performance in certain tasks. You might also see an entanglement-based component that handles jobs which aren't otherwise possible, like spy-proof quantum cryptography. This breakthrough isn't going to change semiconductors overnight, but it could make quantum computing more of a practical reality.