Chinese scientists set new distance record for quantum cryptography via entangled photons
As the role of information and its secure communication becomes more and more central to our lives, scientists work on ways to provide “hacking free” methods of transmitting information. Quantum Communication is an exciting development in this field that uses the exotic properties of particles described through quantum mechanics to enable hacking-proof communication. While lab based tests on quantum communication have been successfully performed over the past few years the big challenge from the applications point of view has been to be able to provide hacking free secure communication over long distances via quantum communication. In a landmark enterprise Chinese scientists have managed to transmit information over 1200 km using the world’s first quantum experiment satellite called the Quantum Experiments at Space Scale (QUESS) satellite Micius.
Entangled photons were sent to Delingha and Lijiang in China with the quantum communications satellite Micius (illustrated).
In the spacecraft’s first record-breaking accomplishment, reported June 16, 2017 in Science, the satellite used onboard lasers to beam down pairs of entangled particles, which have linked quantum properties, to two cities in China, where the particles were captured by telescopes. The quantum link remained intact over a separation of 1,200 kilometers between the two cities — about 10 times farther than ever before. Two other major achievements of these experiments were the demonstration over long distances of quantum teleportation, a process that transmits the properties of one particle to another particle. This development is expected to be very useful for linking up future quantum computers, making the machines more powerful. Finally Micius was able to demonstrate quantum key distribution — using entangled particles to exchange keys between the ground and the satellite. According to experts the satellite is a major development where Chinese researchers have had to seriously upgrade the existing quantum communication technology while reducing the size of apparatus to function in space.
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