China launches world's first quantum communication satellite

The primary task of the craft will be to demonstrate quantum key distribution between the satellite and two stations on the ground.

Aaron Sims | Oct 01, 2016

   

China has launched the world's pioneer Satellite dedicated to studying the fundamentals of Quantum communications in space. At an estimated $100 million, the Quantum Experiments at Space Scale was launched from the Jiuquan Lunch Center in northern China.

Also named "Mencius" after the ancient Chinese Philosopher, the craft is expected to demonstrate the feasibility of quantum communication between Earth and space and also test quantum entanglement over unprecedented distances.

The work on the aircraft began in 2011, and the assembly was completed early this year. The craft weighs 600 kilograms and will be placed in earth orbit approximately above 500km above ground. Its primary instrument is a "sagnac" interferometer that will be used to generate two entangled infrared photons by shining an ultraviolet laser on a nonlinear optical crystal.

Previous attempts by physicists have led to the separation of entangled photons in distances of up to 300 miles on earth. But it has been difficult to send photons for longer distances because photons scatter when they travel down optical fibers or when they collide with atmospheric turbulence when sent between the telescopes.

This has necessitated the performance of the experiments in space. The primary task of the craft will be to demonstrate quantum key distribution between the satellite and two stations on the ground.

It will perform a test of Bell's inequality at a separation of 1200k- the greatest distance ever attempted- to prove that entanglement can take place between two particles separated by such a large distance. These goals will be performed solely by the Chinese team.

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