Italian researchers conduct an experiment to prove that quantum communication is possible on a global scale

Researchers from Italy have published a research paper showcasing that quantum communication is feasible between high-orbiting satellites and a station on the ground. This new research proves that quantum communication is possible on a global scale by using a Global Navigation Satellite System (GNSS).

The reports of the study are presented in a paper published last week titled Towards quantum communication from global navigation satellite system. In the experiment conducted, a single photon was exchanged over a distance of 20,000km between a ground station and a high-orbit satellite. The exchange was between the retroreflector array mounted on Russian GLONASS satellites and the Space Geodesy Centre on the Earth, Italian space agency. The challenge in high-orbit satellites is that the distance causes high diffraction losses in the channel.

One of the co-authors, Dr. Giuseppe Vallone, University of Padova said to IOP Publishing: “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.”

He mentions that the crux of such systems is to safely transmit information from satellites in the air to the ground. It is important that these channels be protected from interference by third parties. “Space quantum communications (QC) represents a promising way to guarantee unconditional security for satellite-to-ground and inter-satellite optical links, by using quantum information protocols as quantum key distribution (QKD).”

The quantum key distribution (QKD) protocols used in the experiment guarantee strong security for communication between satellites and satellites to Earth. In QKD, data is encrypted using quantum mechanics and interferences are detected quickly.

Another co-author, Prof. Villoresi talks to IOP Publishing about their focus on high-orbit satellites despite the challenges: "The high orbital speed of low earth orbit (LEO) satellites is very effective for the global coverage but limits their visibility periods from a single ground station. On the contrary, using satellites at higher orbits can extend the communication time, reaching few hours in the case of GNSS.”

After the experiments, the researchers estimated the requirements needed for an active source on a GNSS satellite. They aim towards QC from GNSS with state-of-the-art technology.

This does not really mean faster internet/communication as only a single photon was transmitted in the experiment. This means that transferring large amounts of data quickly, i.e., faster internet is not likely gonna happen with this application. However, it does show that data transmission can be done over a large distance with a secure channel.

For more details, you can check out the research paper on the IOPSCIENCE website.