Ultrafast Optical Processing Group, Institut National de la Recherche Scientifique

Researchers Have Built the Most Complex Light-Based Quantum Computer Chip Ever

Bring on quantum computers that process data at the speed of light.

14 MAR 2016

In a world-first, researchers have created a quantum chip that contains four entangled particles of light, known as photons, and is capable of performing actions over hundreds of channels simultaneously.

Or to put that into context, they've come closer than ever before to building a chip that's similar to the ones in our smartphones and computers, but that has the potential to perform exponentially more calculations, and can process data at the speed of light. Sounds good, right?


"This represents an unprecedented level of sophistication in generating entangled photons on a chip," said co-lead researcher David Moss, from Swinburne University of Technology in Australia.

"Not only can we generate entangled photon pairs over hundreds of channels simultaneously, but for the first time we’ve succeeded in generating four-photon entangled states on a chip."

Quantum computing is an extremely powerful system based on entangled particles. When two particles are entangled, they're inextricably linked, so whatever happens to one immediately affects its partner, even if they're miles apart.

That's useful in computing - which is currently governed by 1s and 0s - because entangled particles can be not only either in the 1 or the 0 state, but also in something called superposition, which gives them a whole lot more processing power - we're talking computers that could crunch all of the world's data to try and solve a problem and spit out a solution within hours.

Today's computer chips use different electron states to code for those 0s and 1s, and a lot of of quantum computing research so far has focussed on entangling electrons to take computers to the next level. But there's a growing interest in using photons instead, because they have the handy ability of being able to move at the speed of light.

That's important, because we already use photons to send information a break-neck speeds via fibre optic cables, but right now, that information has to be slowed down and translated back into electrons in order to be received by your computer. Bummer.

Instead, imagine a computer that's not only able to process photons, but could also do so at a quantum level, with unprecedented processing power. That's exactly what the Swinburne team has just taken us a step closer to achieving with their new record-breaking quantum chip.

The chip was created by using something called 'optical frequency combs', "which, unlike the combs we use to detangle hair, actually help to 'tangle' photons on a computer chip", the team explains.

This allowed them to create entangled photon states with more complexity than ever before, over many parallel channels, which gives the chip better functionality. 

Most impressively, the chip was created with processes that are compatible with the computer chips we use today - which means they could one day be scaled up and incorporated directly into laptops or cell phones. 

"By achieving this on a chip that was fabricated with processes compatible with the computer chip industry we have opened the door to the possibility of bringing powerful optical quantum computers for everyday use closer than ever before," said co-lead researcher Roberto Morandotti, from the Institut National de la Recherche Scientifique in Montreal, Canada.

There's still a lot of work to do to, because although this is the most complex chip of its kind, it's still incredibly simple compared to the chips we currently use. But the researchers point out that the set-up they've created is scalable, which means it's only up from here. Bring on the next era of computing.

The research has been published in Science.

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