Science

Jedi scientists freeze light in midair to bring quantum computers a step closer to reality

Jedi scientists freeze light i...
Geoff Campbell and Jesse Everett
Geoff Campbell and Jesse Everett
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Geoff Campbell and Jesse Everett
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Geoff Campbell and Jesse Everett

Remember that scene in "The Force Awakens" where the dark side warrior Kylo Ren stops a laser blast in mid-air? In a Canberra laboratory, physicists have managed a feat almost as magical: they froze the movement of light in a cloud of ultracold atoms. This discovery could help bring optical quantum computers from the realms of sci-fi to reality.

The experiment, published in a paper this week, was inspired by a computer stimulation run by lead researcher Jesse Everett from the Australian National University. The researchers used a vaporized cloud of ultracold rubidium atoms to create a light trap, into which they shone infrared lasers. The light trap constantly emitted and re-captured the light.

"It's clear that the light is trapped – there are photons circulating around the atoms," Everett says. "The atoms absorbed some of the trapped light, but a substantial proportion of the photons were frozen inside the atomic cloud."

This is not the first time physicists have stopped light, but it is the first experiment that was designed to prove beyond doubt that the trapped light was rendered stationary. The atomic cloud was imaged from the side as one method of confirming the theory.

Knowing that scientists can now stop the movement of light is an exciting development because it could allow the interactions of light and atoms to be manipulated with the extreme precision needed to develop quantum logic gates – the building blocks of the quantum computer model.

Conventional electronic computers work with units of data called bits. Bits are dependent on whether power is moving through a wire or not. They're either on or off, which we assign as a state of 1 or 0.

In conventional computing, logic gates are simple electronic circuits that can compare the on/off states of one or two incoming currents and then send on a new outgoing current according to the combined state of these incoming currents. The gates use combinational logic to serve as the building blocks of the most complex digital circuits.

Because of the complexity of the way light works, quantum bits, called qubits, can assume more complex states than electronic bits. If we can get quantum computing right, we should be able to assign each qubit a state of 0, 1, or both states at once. This ability to assume multiple states is the reason quantum computing is such an inspiring idea – it should be able to perform many different operations at once, at incredible speeds.

At this stage, we're still looking for a reliable, scalable quantum logic gate that can communicate with two qubits at once. That's why the race is on to find new ways to get photons (the particles that make up light) to interact with each other.

Co-researcher Geoff Campbell from ANU explained that while photons generally pass by each other at the speed of light without any interactions, atoms interact with each other more readily.

"Corralling a crowd of photons in a cloud of ultra-cold atoms creates more opportunities for them to interact," Campbell says.

Optical quantum computers could connect easily with fibre optics and reolutionize the way we manage big data in fields such as medicine, defence, telecommunications and financial services.

"Optical quantum computing is still a long way off, but our successful experiment to stop light gets us further along the road," says Everett.

The study appears this week in Nature Physics. The researchers talk more about their work and its possibilities in the video below.

Source: ANU

Quantum computing a step closer to reality

6 comments
ChrisWalker
i'll say it again, so, this experiment helps prove my theory that Saturns rings can hold light as the Hexagon shaped storm acts like a laser vortex chip to process the information stored in the light for a really huge supercomputer. and if you look at the composition of Uranus and Neptune whose atmospheres produce massive amounts of electricity, the concept of liquid light semiconductors using quantum entanglement becomes more realistic for such a supercomputer.
Bob Flint
Stopping light, could moving it backwards be the next step to time travel?
Douglas Bennett Rogers
Ordinarily, photons only exist at the speed of light. Don't know if this qualifies as a photon. How is the energy expressed?
Daniel Gregory
How does it travel to meet someone's eye if the photon is physically trapped in a frozen cloud? Is it possible that a photon is a carry of light, and not an expression of it?
SapphireSpire
I don't know much about QM but it sounds to me like there's more to light than meets the eye. Laser 'blasts' in Star Wars are too slow to be pure light. Laser rifles work by using a high energy laser to super heat a small pellet and then launch it as a bolt of plasma. A bolt of plasma is what Kylo Ren stopped in "The Force Awakens".
noteugene
And here I am still using AOL..........