Quantum Teleportation | Chinese scientists successfully transmitted the information between two entangled particles through seawater, a type of quantum communication for the first time underwater.

In this concept demonstration experiment, the information was transmitted through a 3.3-meter seawater tank. But scientists estimate they could use this technique to send secure information at a distance of nearly 900 meters through open water.

“People talked about the idea of underwater quantum communication before, but I do not know anyone who did a similar experiment,” said Devin Powell of New Science, Thomas Jennewein of the University of Waterloo, Canada.

“An obvious application could be a submarine that wants to remain submerged, but to communicate safely.”

This is a great achievement because of quantum communication – known as quantum teleportation – promises people the possibility of transmitting messages protected by curiosity eyes by using the laws of physics. This is extreme encryption. It is based on the idea of quantum inseparability – a strange phenomenon called Einstein “remote sinister.” In short, quantum inseparability is achieved when two particles become inextricably linked to each other so that whatever happens to one of them, it will automatically affect each other no matter how far apart they are. Through this mechanism, scientists have already “teleported” information at great distances through the optical fibre and even through the open space.

At the start of this year, a separate team of Chinese researchers managed to use quantum inseparability to teleport information to a satellite on Earth’s orbit over a distance of more than 500 km. But so far no one has done the same thing in the water, which is known for the fact that it diffuses everything we try to radiate through it. You just have to think about how a laser pointer lights in air and water. For this experiment, researchers at Shanghai Jiao Tong University have filled a 3-meter water tank in the Yellow Seawater.

Then they created a pair of inseparable photons by pulling a beam of light through a crystal. Regardless of the polarization of one of the photons, the other automatically received the opposite polarization. These particles were placed at opposite ends of the reservoir, after which the team showed that, although separated by meters of seawater, they could transmit the information accurately to each other in 98 per cent of the cases.

“Our results confirm the possibility of a quantum channel in water, which is the first step towards underwater quantum communication,” researchers write in The Optical Society.

It is only at an early stage, and it is important not only that other teams reproduce this result now but also see if the same can be done over long distances through seawater not only a reservoir. Team calculations predict that it would be possible to achieve quantum communication through open water at a distance of 885 meters using photons. But New Scientist reports that other groups have calculated an underwater quantum communication limit of just 120 meters.

“Because ocean water absorbs light, expanding this is difficult to achieve,” said Powell, Jeffrey Uhlmann of the University of Missouri, Colombia, USA.

How hard we can extend this underwater quantum communication remains to be seen, at this stage, the researchers have shown that this is possible. It is just a matter of time until the limits begin to expand. The research was published in the Optical Society.

Quantum teleportation

Quantum teleportation is a process by which quantum information (e.g., the well-determined state of an atom or photon) can be transmitted from one place to another through classical communication and a pre-existing quantum inseparability between the emitter and the receiver. Since it depends on classical communication, quantum teleportation cannot be used for the transfer or communication of superluminal speed data.

Apart from names, there is no link between quantum teleportation and teleportation in science fiction. Quantum teleportation is a transfer of information; it is not a form of transport but communication.

It is a way to transfer a quantum bit from one place to another without carrying a physical particle. This process can not be used to make copies of a system. In May 2014, a TU Delft University Researchers team published the study “Unconditional Quantum Teleportation between Distant Solid State Quantum Bits,” claiming that it managed to beam data between qubits over a distance of 3m with a 100% accuracy.

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