Photons Quantum Teleported 60 Miles Across Lake

May 16, 2012 Updated: October 1, 2015
Epoch Times Photo

The potential for perfectly encrypted satellite-based telecommunications just moved a big step closer to reality, with a new quantum teleportation record set by Chinese physicists.

A team of researchers in Shanghai transferred information about photons (light particles) across a distance of 97 km (about 60 miles) using quantum entanglement, breaking their previous record of 16 km (nearly 10 miles) set in 2010.

In quantum entanglement, two objects or qubits are connected in a manner that prevents understanding what one object is experiencing without acknowledging the other one. Albert Einstein referred to this concept as “spooky action at a distance,” whereby although the objects are physically separate, factors that affect one also affect the other.

Quantum teleportation is different from classical teleportation. As the particles are connected but not actually transported, this means that encrypted information can be relayed without its being intercepted.

“Long-distance quantum teleportation is of particular interest and has been one of the holy grails of practical quantum communication,” wrote the researchers in their study abstract.

The scientists employed a technique called acquiring, pointing, and tracking (APT) to send the information across Qinghai Lake, the largest lake in China. The altitude there is above 3,000 meters (about 10,000 feet), hence reducing any atmospheric turbulence due to weather conditions.

They used a 1.3-watt laser and powerful optics to improve transmission, and pairs of entangled photons appeared simultaneously at two separate locations.

Despite loss of qubits due to beam spreading, the researchers teleported 1,171 photons in four hours across a distance one order of magnitude greater than their 2010 experiment.

“Our results show that even with high-loss ground to satellite uplink channels, quantum teleportation can be realized,” concluded the researchers in their paper.

“Furthermore, our APT system can be used to track an arbitrarily moving object with high frequency and high accuracy, which is essential for future satellite-based ultra-long-distance quantum communication.”

The findings were published online in arXiv on May 9 and can be accessed here

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