Wednesday, September 20, 2017

Is quantum communication the future?

Dr KK Aggarwal

For the first time, entangled particles of light have been successfully transmitted through sea water, which is known to absorb light, in a feat that can be called as ‘quantum communication’ or ‘quantum teleportation’.

Researchers from the Shanghai Jiao Tong University in China tested entanglement of photons in water in a proof-of-concept experiment. Saltwater from the Yellow Sea was put in a container. And, they were able to transmit entangled photons through the seawater in the 3.3 meter long container without disturbing their quantum link. In the study published in the journal The Optical Society, the researchers said, “Our results confirm the feasibility of a seawater quantum channel, representing the first step towards underwater quantum communication.”

This experiment was based on the concept of “quantum entanglement”, a concept that was once considered impossible by Einstein, who termed this phenomenon as "spooky action at a distance". 

Matter, we know, can be sequentially converted into atoms and then to subatomic particles (protons, electrons and neutrons), photons, quantum and wave. A photon (or quantum) has properties not only of a wave but also of a particle simultaneously (wave particle duality).

When two photons interact or become “entangled” and then separate, they are connected at a speed much faster than the speed of light and affect each other, even when separated by huge distances. In this entangled state, the two photons (or quantum bits – qubits) share an existence or characteristics (quantum information measured as quantum bits ‘qubits’) and are interdependent. When one is altered in any way, the other too is altered even at a distance. 

Transmission of quantum information from one location to another is called quantum communication or quantum teleportation.

All communication today is local i.e. antenna, wires, cables, optical fibers are required for transmission of information. Wireless communication includes applications such as two-way radios, cellular telephones, personal digital assistants and wireless networking (Wikipedia). Quantum communication or teleportation, on the other hand, is indicative of non local connectivity.

This proof of quantum communication has raised possibility of ‘quantum’ internet in the future and also that transmitting ‘quantum’ information or messages underwater without fear of their being intercepted may soon be a reality.

Disclaimer: The views expressed in this write up are entirely my own.

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