Successfully completed the three major tasks "Mozi" seized the commanding heights of quantum technology innovation
Our reporter Wu Changfeng
The "Mozi" quantum science experimental satellite (hereinafter referred to as "Mozi") that travels in space has its own "official name."
On September 11, 2020, the national major cultural project "Cihai" (seventh edition) was officially released to the public. This new content added the terms "quantum communication" and "quantum science experimental satellite".
In 2016, my country successfully launched the world's first quantum satellite-"Mozi", and successfully completed the three major scientific goals of satellite-to-earth quantum key distribution.
In 2017, the world’s first thousand-kilometer quantum secure communication trunk line, the Beijing-Shanghai trunk line, was completed and put into use. Combined with the "Mozi", my country successfully realized the world’s first intercontinental quantum secure communications... During the "13th Five-Year Plan" period, my country was A series of major advances have been made in the field of quantum technology.
Surprisingly beyond life expectancy
"Mozi" was successfully launched at the Jiuquan Satellite Launch Center on August 16, 2016, and the scientific experiment was officially launched on January 18, 2017.
"The'Mozi' successfully achieved all three predetermined scientific goals, laying a solid scientific and technological foundation for my country to continue to lead the world in the development of quantum communication technology and to examine the frontier research on fundamental issues of space-scale quantum physics in the future." China Science and Technology University professor Pan Jianwei said.
The satellite-to-earth high-speed quantum key distribution is one of the scientific goals of "Mozi".
"Mozi" has established an optical link with Hebei Xinglong Terrestrial Optical Station. At a communication distance of 1,200 kilometers, the transmission efficiency of the satellite-to-ground quantum key is 20 orders of magnitude (trillion times) higher than that of the terrestrial fiber channel at the same distance.
Realizing quantum teleportation from the Earth to the stars is another scientific goal of the "Mozi".
Quantum teleportation can use quantum entanglement to accurately transmit an unknown quantum state of a particle to a remote location without transmitting the particle itself.
The "Mozi" quantum teleportation experiment uses the method of launching entangled photons from the ground and receiving them from the sky.
The experimental communication distance ranges from 500 kilometers to 1,400 kilometers, and all 6 states to be transmitted exceed the classical limit with a confidence level greater than 99.7%.
Quantum entanglement was called "ghostly super-distance action" by Einstein.
Does this effect still exist at greater distances?
Will it be affected by other factors such as gravity?
As one of the satellite's three major scientific experiment tasks, the "Mozi" carried out the quantum entanglement distribution experiment on the space scale for the first time in the world.
On June 15, 2020, "Mozi" achieved the first thousand kilometers-level entanglement-based quantum key distribution in the world, which increased the spatial distance of the previous groundless quantum secure communication by an order of magnitude.
It is reported that the "Mozi" is expected to exceed its life expectancy, continue to work for at least two years, and start more international cooperation.
The most dazzling "science star" in space
A series of scientific experimental results obtained by "Mozi" have won praise from the international community and opened the door to the era of global quantum communication.
The realization of satellite-to-earth quantum key distribution has laid a reliable technical foundation for building a quantum secure communication network covering the world.
Based on this, the satellite can be used as a reliable relay station to realize key sharing between any two points on the earth and expand the scope of quantum key distribution to the world.
In addition, by interconnecting the quantum communication ground station with the inter-city optical fiber quantum secure communication network, it is possible to build a world-wide integrated secure communication network.
After the completion of the three scheduled scientific experiment tasks, in early 2018, through international cooperation with the Austrian Academy of Sciences, the "Mozi" realized for the first time the intercontinental quantum secure communication between Beijing and Vienna about 7,600 kilometers apart.
This achievement was also selected as one of the top ten progresses in international physics in 2018.
In 2018, Pan Jianwei's team won the "Wolf Prize in Physics", which is known as the vane of the Nobel Prize.
The introduction of the winners specifically mentioned: "Quantum key distribution has been able to achieve hundreds of kilometers in optical fibers, and the other is the 1,200 kilometers of stars and grounds achieved by "Mozi".
On January 31, 2019, the "Mozi" research team was awarded the 2018 Cleveland Prize.
This is the first time that Chinese scientists have won this important honor for their achievements in local research in more than 90 years.
So far, the "Mozi" research team has published 5 research papers in the journals "Nature" and "Science", which has laid a solid foundation for my country to continue to lead the development of world quantum communication technology and test the frontier research of basic problems of quantum physics at space scale in the future. The scientific and technological foundation of
The international authoritative journal "Nature" once evaluated: The research results of "Mozi" marked the rise of China in the field of quantum communication and will lead Europe and North America.