Quantum Computers a Step Closer to Reality

Melbourne: Physicists have brought quantum computers - which could solve problems too complex for today's most advanced machines - a step closer to reality by successfully stopping light in a new experiment.

Lead researcher Jesse Everett from Australian National University (ANU) said controlling the movement of light was critical to developing future quantum computers. Optical quantum computing is still a long way off, but our successful experiment to stop light gets us further along the road, said Everett.

He said quantum computers based on particles of light - photons - could connect easily with communication technology such as optic fibres and have potential applications in fields such as medicine, defence, telecommunications and financial services. The research team's experiment - which created a light trap by shining infrared lasers into ultra-cold atomic vapour - was inspired by Everett's discovery of the potential to stop light in a computer simulation. It's clear that the light is trapped, there are photons circulating around the atoms, Everett said.

The atoms absorbed some of the trapped light, but a substantial proportion of the photons were frozen inside the atomic cloud, he said. Everett likened the team's experiment to a scene from Star Wars: The Force Awakens when the character Kylo Ren used the Force to stop a laser blast mid-air. It's pretty amazing to look at a sci-fi movie and say we actually did something that's a bit like that, he said.

Associate Professor Ben Buchler, who leads the ANU research team, said the light-trap experiment demonstrated incredible control of a very complex system. Our method allows us to manipulate the interaction of light and atoms with great precision, said Buchler. Co-researcher Geoff Campbell from ANU said photons mostly passed by each other at the speed of light without any interactions, while atoms interacted with each other readily.

Everett likened the team’s experiment to a scene from Star Wars: The Force Awakens when the character Kylo Ren used the Force to stop a laser blast mid-air. It’s pretty amazing to look at a sci-fi movie and say we actually did something that’s a bit like that, he said.

Corralling a crowd of photons in a cloud of ultra-cold atoms creates more opportunities for them to interact, said Campbell. We're working towards a single photon changing the phase of a second photon. We could use that process to make a quantum logic gate, the building block of a quantum computer, he said.

The research was published in the journal Nature Physics.

Source: PTI