Jul 13, 2017

Here's How Scientists Teleported the First Object Into Space

Scientists from China have just performed the first ever quantum teleportation from Earth to space. Does this mean we are now living in the future envisioned in Star Trek?

Actually, no physical matter was actually “beamed up,” unfortunately — just photons. But this breakthrough might make for a better and more secure internet in the future.

"Quantum teleportation brings to mind Star Trek’s transporter, where crew members are disassembled in one location to be reassembled in another,” explained astrophysicist Brian Koberlein from the Rochester Institute of Technology. “Real quantum teleportation is a much more subtle effect where information is transferred between entangled quantum states. It’s a quantum trick that could give us the ultimate in secure communication."

Long-distance quantum communication has been recognized as a keystone for things like large-scale quantum networks and quantum computation. But previous quantum communications — or “teleportation” — experiments have seen limited success.

Entanglement is a tenuous state, with the link easily broken. Previous attempts using fiber networks have been limited to distances of 100 km or less due to photon loss inside the fiber. Some of the first attempts at “over-the-air” teleportation using light beams were only successful at night because of daytime atmospheric turbulence.

“An outstanding open challenge for a global-scale ‘quantum internet’ is to significantly extend the range for teleportation,” wrote Ji-Gang Ren and his colleagues in their new paper about the teleportation feat. They said that the most promising solution to the distance problem is to exploit satellites, which can “conveniently connect two remote points on the Earth with greatly reduced channel loss because most of the photons’ propagation path is in empty space.”

The weird phenomenon of entanglement might seem difficult to fathom, but it occurs when two quantum objects, such as photons, form at the same instant and point in space. Basically, they share the same existence and the state of one object affects the state of the other. But in theory, this shared existence should continue even when the photons are separated by long distances.

“For quantum teleportation, one of these entangled objects is measured in combination with the object to be ‘teleported,’” explained Koberlein, who was not involved with the research, “and the result of this measurement is then sent to another location, where a similar combined measurement is made. Since the entangled objects are part of both measurements, quantum information can be teleported.”

For the latest attempt by the Chinese researchers, they used a new satellite called Micius that was launched last year by a Long March rocket. The satellite contains an extremely sensitive photon receiver that can detect the quantum states of single photons transmitted from the ground.

They used several techniques to “optimize the link efficiency and overcome atmospheric turbulence,” including a “compact ultra-bright source of multi-photon entanglement, narrow beam divergence, high-bandwidth and high-accuracy acquiring, pointing, and tracking.”

They were successful with quantum teleportation from Earth to space at distances of up to 1,400 km, the furthest ever. The link-up wasn’t 100 percent successful however, as out of millions of photon states they attempted to transmit into space, just over 900 of them were successful.

Read more at Discovery News

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