Groundbreaking photonic chip could spark Quantum Computing revolution

A multi-purpose optical chip which generates, manipulates and measures entanglement and mixture – two quantum phenomena that are essential driving forces for tomorrow’s quantum computers – have been developed by researchers from the University of Bristol’s Centre for Quantum Photonics. This work represents crucial breakthrough within the race to develop a quantum computer.

The elemental resource that drives a quantum computer is entanglement – the relationship between two distant particles which Einstein famously called ‘spooky action at a distance’. The Bristol researchers have, for the 1st time, shown that this remarkable phenomenon could be generated, manipulated and measured entirely on a tiny silica chip. They’ve got extensively utilized the similar chip to measure mixture – a frequently unwanted effect from our environment, but a phenomenon that could now be controlled and used to characterize quantum circuits, in addition to being of fundamental interest to physicists.

“On the way to build a quantum computer, we not just should be in a position to control complex phenomena corresponding to entanglement and mixture, but we have to have the ability to do that on a chip, in order that we will be able to scalably and practically duplicate many such miniature circuits – in much an identical way because the modern computers we’ve today,” says Professor Jeremy O’Brien, Director of the Centre for Quantum Photonics. “Our device enables this and we believe this is a major breakthrough towards optical quantum computing.”

The chip, which performs several experiments that could each ordinarily be achieved on an optical bench the dimensions of a big dining table, is 70 mm by 3 mm. It includes a network of tiny channels which guide, manipulate and engage single photons – particles of sunshine. Using eight reconfigurable electrodes embedded within the circuit, photon pairs might be manipulated and entangled, producing any possible entangled state of 2 photons or any mixed state of 1 photon.

“It is not ideal in case your quantum computer can only perform a single specific task”, explains Peter Shadbolt, lead author of the study, that is published within the journal Nature Photonics. “We might favor to have a reconfigurable device which may perform a broad sort of tasks, very like our desktop PCs today – this reconfigurable ability is what we have demonstrated. This device is approximately ten times more complex than previous experiments using this technology. It’s exciting because we are able to perform many alternative experiments in an exceedingly straightforward way, using a single reconfigurable chip.”

The researchers, who’ve been developing quantum photonic chips for the past six years, are actually engaged on scaling up the complexity of this device, and notice this technology because the building block for the quantum computers of the longer term.

Dr Terry Rudolph from Imperial College in London, UK, believes this work is an important advance. He said: “Having the ability to generate, manipulate and measure entanglement on a chip is a terrific achievement. Not just is it a key step towards the various quantum technologies – similar to optical quantum computing – that are going to revolutionize our lives, it gives us a lot more opportunity to explore and play with probably the most very weird quantum phenomena we still struggle to wrap our minds around. They’ve made it really easy to dial up in seconds an experiment that used to take us months, that i wonder if even i will be able to run my very own experiment now!”

Paper

‘Generating, manipulating and measuring entanglement and mixture with a reconfigurable photonic circuit’ by P. J. Shadbolt, M. R. Verde, A. Peruzzo, A. Politi, A. Laing, M. Lobino, J. C. F. Matthews, M. G. Thompson and J. L. O’Brien in Nature Photonics