Bristol boffins announce quantum cloud

Ever wanted to fiddle with a quantum computer, but don't have the sort of connections to get you inside a lab? If so, the boffins at Bristol University have just the thing for you: a "quantum cloud"!

The wonk-run quantum cloud will give researchers and the general public the chance to book time on a diminutive quantum chip housed in the university's qubit-wrangling research lab. The service was announced on Friday, and beginning September 20th will give people access to a quantum simulator to test out quantum-ish computations, plus the opportunity to apply to have their experiments run on Bristol's quantum photonic processor.

The catch is that it's a pretty weedy quantum chip. The Bristol chip generates a photon using a blue laser that is split into two red daughter photons. These photons are prepared as qubits – the quantum equivalent of a digital bit, except these can exist in superposition of states which can be manipulated using electrodes acting as phase shifters that change the speed of the photons via wave guides, which "behave like optical fibres and channel the photons around the chip," the researchers write.

The Bristol chip measures some 70 by 3mm and was first announced in 2011. Though it may not have many qubits, its diminutive size was seen as a breakthrough in a field known more for room-size installations than matchbox chips.

By comparison, NASA and Google are fiddling with a quantum-ish processor from controversial company D-Wave systems. That chip can field around 512 qubits, housed inside a superconducting chip cooled to 20 millikelvin that sits inside a 10–square meter shielded room.

Though Bristol's chip does not allow for the programming of sophisticated problems, as D-Wave's system does, it does give world+dog a chance to run experiments on a real quantum system – for free.

"The quantum processor chip that we have developed is in our lab here in Bristol and we continue to work on it, so it is very much at the cutting edge of science," the researchers write. "The quantum processor in our lab will allow you to create and manipulate your own qubits and measure the quantum phenomena of superposition and entanglement. The processor works by repeatedly sending the prepared photons through the circuit and measuring where the photons emerge. Over many iterations this data builds up a statistical picture ... that tells you what is happening to the photons."

Once people gain access to the "QCloud" they can use the chips to create entanglement between the photon pairs, manipulate the photons' states, and measure impacts on the photons from the outside environment.

The public can also access a quantum simulator, which lets them test out potential quantum experiments in a software simulation of the quantum hardware, which the Bristol boffins promise is "an exceedingly close representation of the real device and is great for trying out different experiments without having to use the real quantum processor." A full reference guide for the simulator is available, and users wishing to test out the chip available through the QCloud will want to fiddle with the "CNOT-MZ" option.

"It's incredibly exciting to think what might be achieved by making this more widely accessible, not only to the brightest minds already working in research, but to the next generation," writes project leader Professor Jeremy O'Brien in a canned statement. "I hope that by helping schools to access this technology, and working with the British Science Association to provide educational content around quantum computing, we can achieve incredible things." ®