CRI听力:?Quantum satellite to conduct more experiments in future: scientist

Chinese scientists say they've successfully completed all their planned experiments with the world's first quantum satellite a year ahead of schedule. 

They say they are now devising new studies, and aiming to launch more quantum satellites to build a hack-proof global quantum communications network 

In an article published in the respected scientific journal, Nature, the Chinese Academy of Sciences has announced that the world's first quantum satellite has achieved its three major scientific objectives, namely, quantum key distribution, quantum entanglement distribution and quantum teleportation.

Karl Ziemelis, chief physical sciences editor of the Nature, says it's an impressive achievement.

"With the publication of these two new papers, Professor Jianwei Pan and his colleagues have completed their demonstration of a trio in the physical sciences. This group has been able to push research in practical quantum communication technologies to such an astronomical height." 

Pan Jianwei, lead scientist of the project, also hails the accomplishment.

"We're very pleased. We have completed all the targets of this scientific experiment within one year, which we had anticipated would take two years."

All the experiments were conducted with the world's first quantum satellite "Micius" during the past year after it was launched. 

In a milestone experiment, the satellite sent quantum keys to ground stations in Hebei and Xinjiang.

The quantum key technology, by harnessing quantum entanglement, can rule out the possibility of wiretapping.

This is based on the theory that the quantum state of the key, once intercepted or measured, will change, and the information being intercepted will self-destruct.

But in practice, the achievable distance for quantum key distribution has been limited to a few hundred kilometers, due to the loss of photons in transmission through optical fibers.

In China's experiment, the communication distance varied from 650 kilometers to 1,200 kilometers, and the transmission rate was up to 20 orders of magnitude more efficient than that expected using an optical fiber of the same length.

Scientist Pan says this can meet the demand of making an absolute safe phone call or transmitting a large amount of bank data.

The Chinese research also involves teams in Austria, Germany and Italy.

Pan says, in next month, they will probably begin to explore the possibilities of intercontinental quantum key distribution in Europe and Asia.

But he also admits that more tests are needed before the quantum satellite can be used practically. 

"This is within our research domain. As for the application domain, we've already negotiated with multiple related institutions for professional usage in China and hopefully (they) can develop our technology to apply it on some mobile targets, such as our frigates and institutions functioning abroad to see if the long-distance quantum communication can be effectively carried out with these mobile targets."

Pan's team aims to build a ground and space integrated quantum communications network in the next 10 years, and apply it in such fields as national defense, finance and energy as well as in exploring basic physical theories such as quantum gravity.