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There’s a limit to how fast information can move through the universe, just like there’s a limit to how fast everything else can move through the universe. It’s a rule. But a team of quantum physicists, like quantum physicists often do, has figured out how to bend it.

Under normal circumstances, the ultimate limit on information transfer—the bandwidth of the universe—is one bit per fundamental particle, moving no faster than the speed of light. That’s in the “classical universe," the way things behave before quantum physics gets involved.

Here’s where that limit comes from: If you want to get a message made up of the bits “1" or “0" to your friend a light-year away and all you have is a single photon, you can encode that single binary number into the photon and send it whizzing off toward your friend at light speed. That friend will receive the message a year later. If your friend wants to use that photon to get a binary message back to you, you’ll have to wait another year. If you want to send more information in that time, you’re going to need more photons. 

But in a new paper published Feb.8 in the journal Physical Review Letters, a pair of a quantum physicists showed that it’s theoretically possible to double that bandwidth.

The technique described in the paper, titled “Two-Way Communication with a Single Quantum Particle,” doesn’t allow you to send your friend two bits with one particle. But it does allow you and your friend to each send one another one bit of information using the same particle at the same time.

If two people want to pull that trick off, the researchers wrote, they have to put the particle in a “superposition of different spatial locations.”

To read more, click here.

Category: Science