A major scientific breakthrough was
announced recently, as satellite-based communication between two ground
stations more than 1,120 kilometers apart was activated by
entanglement-based quantum key distribution (QKD), thereby extending the
distance without compromising security.
by the world's first mobile quantum communication satellite, named Mozi
or Micius after the Chinese philosopher, entangled photon pairs were
distributed via bidirectional downlinks to two ground observatories in
Delingha, Qinghai province and Nanshan, Urumqi, the capital of Xinjiang
Uygur autonomous region.
was jointly conducted by Academician Pan Jianwei, his colleague Peng
Chengzhi and Professor Yin Juan from the Hefei National Laboratory for
Physical Sciences at the Microscale and Department of Modern Physics,
University of Science and Technology of China, in Hefei, Anhui province.
involved in the work were Professor Artur K. Ekert from the
Mathematical Institute at the University of Oxford, as well as
Academician Wang Jianyu and his research team from the Center for
Excellence in Quantum Information at the Shanghai branch of the Chinese
Academy of Sciences.
On June 15, the
researchers published their paper titled "Entanglement-based secure
quantum cryptography over 1,120 kilometers" in the magazine Nature, the
world's leading multidisciplinary science journal.
reviewer at Nature hailed the work as a "groundbreaking experiment,
which takes a significant step towards establishing a global QKD
network, and more generally, a quantum internet for quantum
While speaking at a
recent online press conference, Pan said: "Costs for making and
launching satellites will plummet, allowing a solid foundation to be
laid for the commercial use of satellite-based quantum communication in a
much extensive way." According to Pan, this cutting-edge technology
will reduce satellite payload weights from 10 tons to around 100
However, the physicist
also stressed that the research has so far only been justified
theoretically. It will require an additional six to seven years until
the satellites are able to produce 1 billion pairs of entangled photons
per second to ensure the implementation.
to the paper's abstract, trusted relays have been adopted to extend the
range of QKD from metropolitan areas to intercity and even
intercontinental distances, although this does have the side effect of
posing security challenges.