Austria is getting a quantum internet. With the “Austrian Quantum Fiber Network” (AQUnet), an Austria-wide network of fiber optic lines is to be built that is suitable for the exchange of quantum information and precision measurements. The Research Promotion Agency FFG is funding the project with 2.8 million euros, announced the Technical University (TU) Vienna. Initially, facilities in Vienna and Innsbruck are to be connected to the quantum Internet.

With the five-year project, the renowned quantum physics groups in Vienna and Innsbruck are to be “linked in a new way”, explained the initiator of the project, Thorsten Schumm from the Atomic Institute of the Vienna University of Technology. The academic project partners include the Vienna University of Technology, the Universities of Vienna and Innsbruck and the Federal Office for Metrology and Surveying (BEV).

The “dark fibers”

There is also a group of first users such as the Austrian Academy of Sciences (ÖAW), the Austrian Institute of Technology (AIT) and the Institute of Science and Technology (IST) Austria. “We assume that further partners will join in the course of the project,” said Schumm.

The project is coordinated by the ACOnet association as the operator of the “classic” high-performance data network that has been connecting domestic universities and research institutions with one another for decades. Depending on what is planned in the quantum Internet, fibers can be used that are already used for classic data transfer. But there are also applications that can easily be disturbed. So-called “dark fibers” would be required for these. These are light guides that are always laid as a reserve and are now to be used for the quantum Internet.

With the east-west connection within Austria, the foundation stone is to be laid “in order to then network further within Europe”, explained Bernd Logar, chairman of the ACOnet association. There are similar initiatives in France, Germany and the Czech Republic that represent possible starting points for the project.

Before that happens, there are still many questions to be answered. Because most of the previous experiments ran on fibers used purely for research between more or less neighboring laboratories. It must now be clarified whether “a quantum Internet can be set up on an existing data backbone, what technical difficulties arise, what environmental influences there are, how far quantum information can be passed on without interference, etc.”, emphasized Schumm.

The previous range of the most secure protocol for quantum communication is only a few tens of kilometers. This means that repeater stations have to be built in for the quantum Internet, but these are currently only being researched.

The possible applications are not limited to tap-proof quantum communication. The quantum network should also enable high-precision optical time and frequency measurement, Schumm refers to the expertise of his research group at the Vienna University of Technology. This would enable high-precision measuring methods; like how atomic clocks tick differently at different positions. This allows one to record tiny changes in the distance or height difference between the atomic clocks and thus “learn more about the behavior of the earth, including earthquake predictions,” says Schumm.

In the past, you could call up the concert pitch A and thus a certified frequency of 440 Hertz over the telephone. An optical concert pitch A, which, however, oscillates at 194 terahertz, is to be distributed over the quantum Internet in order to enable such high-precision measurements. (Apa)