Quantum physics, a relatively newer scientific discipline compared to many others, has concerned itself with confirming the existence of some of the smallest particles that compose everything around us.
As the 21st century continues, integrated realities like quantum computing are pushing the boundaries even further; still, the most transformative area of the future and beyond is applying some of the principles for establishing various global networks.
Now, a team of researchers in Italy are sharing the results of a landmark study which tested the feasibility of conducting quantum communications between a ground station and two high-orbiting global navigation satellite systems (GNSS).
Not only did they successfully reach their target, but the single photon level exchange achieved was at a distance of over 20,000 km.
A Dramatic First Step
This is the first time such an exchange has happened between two different satellites: the study involved the Space Geodesy Centre of the Italian Space Agency and the Russian GLONASS constellation.
This improved method offers many benefits, as "high-orbit satellites pose a great technological challenge due to the high diffraction losses of the optical channel, and the experimental investigation of such quantum channels is still lacking," the team stressed.
As co-lead author Professor Paolo Villoresi explained, the experiment allowed the researchers to learn valuable information about how to conduct future work with high-orbiting satellites:
"Our experiment used the passive retro-reflectors mounted on the satellites. By estimating the actual losses of the channel, we can evaluate the characteristics of both a dedicated quantum payload and a receiving ground station."
Establishing a Global Quantum Network
As Dr. Giuseppe Vallone, University of Padova Department of Information Engineering Assistant Professor and study co-lead author shares, constructing a global quantum network will dramatically impact every sector of society:
"Satellite-based technologies enable a wide range of civil, scientific and military applications like communications, navigation and timing, remote sensing, meteorology, reconnaissance, search and rescue, space exploration and astronomy.
The core of these systems is to safely transmit information and data from orbiting satellites to ground stations on Earth. Protection of these channels from a malicious adversary is therefore crucial for both military and civilian operations."
It is a big step in the efforts to build up solid capabilities to support satellite-based quantum communication (QC).
"QC could also offer interesting solutions for GNSS security for both satellite-to-ground and inter-satellite links, which could provide novel and unconditionally secure protocols for the authentication, integrity and confidentiality of exchanged signals," co-lead author Professor Paolo Villoresi commented.
Although this is a historic first, it builds momentum in this emerging area. As Dr. Giuseppe Bianco, Director of the Space Geodesy Centre of the Italian Space Agency and co-author, said, "The single photon exchange with a GNSS satellite is an important result for both scientific and application perspectives.
It fits perfectly in the Italian roadmap for Space Quantum Communications, and it is the latest achievement of our collaboration with the University of Padua which is steadily progressing since 2003."
Details about the study appear in a paper, titled "Towards quantum communication from global navigation satellite system", which was published December 20th in the Quantum Science and Technology journal.