Real-Life Lightsaber: Harvard And MIT Scientists Bind Light Together To Create New Form Of Matter
A team of scientists from Harvard University and MIT have brought to life everyone's favorite fictional weapon: the lightsaber. Well, sort of. For the first time ever, scientists have bound together photons -- massless particles of light that don't normally interact with one another -- to create a new type of photon material. Before you get too excited, know that this breakthrough is more likely to advance quantum computing rather than the arguably more important industry of lightsaber development.
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"It's not an in-apt analogy to compare this to light sabers," said Harvard physicist Mikhail Lukin, who worked on the team. "When these photons interact with each other, they're pushing against and deflecting each other. The physics of what's happening in these molecules is similar to what we see in the movies."
Normally there is no interaction between photons as they pass one another; before now, it was only theoretically possible to get one photon to acknowledge another. But when the Harvard-MIT team threw a bunch of photons into a vacuum chamber containing cold atoms, they noticed something interesting: the photons left the chamber together, as a single molecule. That's an entirely new form of matter.
The photons joined together in the vacuum because of a complex effect known as the Rydberg blockade. In simple terms, when a passing photon excites an atom, a neighboring atom cannot become as excited as the first one. As photons pass through these variously excited atoms, a push-pull force binds them together.
"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," said Lukin. "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. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn't been observed."
The findings are detailed in the paper "Attractive photons in a quantum nonlinear medium" published in the journal Nature.
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