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Scientists find a way to make real lightsabers!

September 26, 2013 1:18pm
Lightsabers, those civilized weapons for a more civilized age, are no longer so far away from becoming real.
Researchers at the Massachussetts Institute of Technology (MIT) have formed a new material made of photons behaving like molecules—something previously deemed purely theoretical, according to

"Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other. What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules," Harvard Professor of Physics Mikhail Lukin said.
Lukin said that while this photonic bound state "has been discussed theoretically for quite a while," it "hadn't been observed" until now.
With colleagues at the Harvard-MIT Center for Ultracold Atoms, Lukin worked with MIT Professor of Physics Vladan Vuletic to have photons bind together to form molecules.
Unlike "conventional" light, Lukin said these "photonic molecules" can push against and deflect each other, "similar to what we see in the movies."
Other researchers in the team included Harvard post-doctoral fellow Ofer Fisterberg, former Harvard doctoral student Alexey Gorshkov and MIT graduate students Thibault Peyronel and Qiu Liang.
Extreme conditions said the researchers, in creating the material, pumped rubidium atoms into a vacuum chamber, and used lasers to cool the atoms to just a few degrees above absolute zero.
When Lukin and colleagues fired two photons into the cloud, they were surprised to see them exit together as a single molecule.
Lukin said this is due to a "Rydberg blockade," which states that when an atom is excited, nearby atoms cannot be excited to the same degree.
He said this means the two photons may push and pull each other through the cloud of atoms, as their energy is handed off from one atom to the next.
"It's a photonic interaction that's mediated by the atomic interaction. That makes these two photons behave like a molecule, and when they exit the medium they're much more likely to do so together than as single photons," he said.
Quantum computers
But Gizmodo noted the researchers have no plans to make weapons out of this. Instead, they hope it will help them build efficient quantum computers.
"Don't let your imagination get too carried away, though. The physicists aren't planning to build futuristic weapons with the new form of matter. Rather they hope it will help them make progress in building efficient quantum computers. Which frankly are futuristic enough in their own right," it said. quoted Lukin as saying photons remain the best possible means to carry quantum information, but added the challenge now is that photons "don't interact with each other."
He said researchers who want to build a quantum computer need to build a system that can preserve quantum information, and process it using quantum logic operations.
But quantum logic requires interactions between individual quanta - and Lukin said what they did might allow them to do this.
Still, he said they still have to improve the performance of what they had created now, though it is important that the physical principles have been established.
3D light structures
Lukin also suggested the system may soon be used to create complex 3D structures like crystals out of light.
"What it will be useful for we don't know yet, but it's a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules' properties," he said. — TJD, GMA News

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