Photon Teleported Between Earth and Space for the First Time

Quantum entanglement is one of the most counter-intuitive and perplexing effects in modern physics. Two objects can be separated by great distances, yet they share the same quantum states. Famed physicist Albert Einstein once described the process of affecting an object in this way as “spooky action at a distance,” and a team of Chinese scientists just took spooky into space. For the first time, quantum “teleportation” has been demonstrated between Earth and an object in space.

China launched its Micius research satellite last year to study the limits of quantum entanglement. The Long March 2D rocket deposited its payload in Sun-synchronous orbit, meaning it passes over the same point on Earth at the same time each day. This allows the team to plan this carefully timed research, which relies upon the highly sensitive photon receiver on the Micius satellite. It’s able to detect the quantum states of single photons projected from the ground.

Researchers have announced the successful communication of quantum information between the ground station and Micius, which is anywhere from 500 and 1,400 kilometers (310-870 miles) above the surface, breaking the distance record for quantum entanglement. This is not teleportation in the Star Trek sense, but quantum teleportation is often cited as a potential basis for high-speed communication and uncrackable cryptography. Basically, when two objects become entangled, they share the same quantum state. From a physics perspective, they’re the same object. The entanglement remains even when the objects are separated by great distances. Thus, changes to one object are immediately replicated by the other.

This sort of teleportation has been accomplished in laboratories on Earth, but the record for distance was around 100 km (62 miles). The problem is that two objects (photons in this case) will only remain entangled if they don’t interact too much with other objects. The atmosphere and fiber optic cables used in experiments will eventually break the bond between two entangled objects. However, it’s easier to control for that in space.

Micius

Most of the transmission distance is in a vacuum, where the photos don’t interact with anything that could break the link. The team worked to lessen the chance photos would be disrupted by building the ground station at an altitude of 4,000 feet in Tibet. The team created entangled pairs of photos at a rate of 4,000 per second, then beamed then beamed half of the pair to Micius. Measurements carried out on the ground and orbiting photos shows that some of them were indeed still entangled.

This process is far from perfect, though. Out of millions of photons sent up to Micius, only 911 of them remained entangled with the ones on the ground. That’s still an impressive result, and one that could help us better understand this spooky action.

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