The next chapter in the story of quantum cryptography and the quantum internet will soon be written between Vienna, Graz, Beijing, the Gobi Desert and low-earth orbit. After many years of preparation, on 16 August 2016 at 1.40 local time the Chinese space station Jiuquan sent a special quantum broadcast station into orbit. Weighing approximately 620 kg, the unit will fulfil an important function while orbiting the earth. In combination with ground stations in Europe and Asia it will now be possible, in the framework of the Austro-Chinese project ‘Quantum Experiments at Space Scale’ (QUESS), to transfer quantum information over around 1,000 kilometres with complete security against eavesdropping, thus laying new foundations for both quantum research and quantum technologies of the future.
Anton Zeilinger, quantum physicist and President of the Austrian Academy of Sciences (OeAW), expressed his delight at the QUESS mission’s successful launch. Together with a team of researchers at the OeAW Institute for Quantum Optics and Quantum Information (IQOQI Vienna) and the University of Vienna, he is heavily involved in the project. ‘Transporting highly sensitive research instruments into space is a complex and difficult undertaking. Hence all QUESS partners are extremely relieved and delighted by the successful launch of the rocket. This represents the first step on the way to worldwide quantum communication,’ explains Zeilinger.
Heinz W. Engl, Rector of the University of Vienna, is also pleased about the successful launch and is following the further development of the project with great interest. After all, quantum physics at the University of Vienna is one of Austrian research’s strongest suits. ‘Together with the OeAW we run the ground station in Vienna, the ’Hedy Lamarr Quantum Communication Telescope’, on the roof of the Institute for Quantum Optics and Quantum Information and have the Chinese Academy of Sciences on board as a project partner. Via this cooperation, which enables basic research at the highest international level, we will do much to drive the quantum internet forward and raise communication around the world to a new level in the long term,’ says Engl.
New quantum records
The successful launch of the mission also makes researchers confident about the coming challenges. The broadcast station’s arrival in space rings in a crucial phase for QUESS, which was formed by the University of Vienna, the OeAW and the Chinese Academy of Sciences in 2010 and is funded by the Federal Ministry of Science, Research and Economy. Its next function is to gain new insights into the quantum entanglement of particles. Dubbed ‘spooky action at a distance’ by Albert Einstein, the term describes a unique connection between two particles that can take on an identical condition independent of the distance between them while being able, in theory, to transfer information over any distance. If for instance measurements are applied to a photon to determine the direction of oscillation of this light particle, its parallel particle briefly takes on the same oscillation.
Previously, Anton Zeilinger and his team had only been able to prove this in an experiment over a record distance of 144 kilometres. Longer distances on the earth’s surface proved impossible due to disturbances in the atmosphere. The quantum physicists thus recognised a way around this in space.
From its orbit, the broadcasting unit will send entangled photons to the ground stations, including the ‘Satellite Laser Ranging Station? at the OeAW Space Research Institute in Graz and the ’Hedy Lamarr Quantum Communication Telescope? at the IQOQI in Vienna. If everything works, the necessary data will be collected and collated here in order to demonstrate for the first time sustained entanglement over larger distances. ’Initial results could even be available this year,’ hopes IQOQI researcher Thomas Scheidl.
The future quantum internet
The project is also bound to attract attention from beyond basic research however. For the quantum physics phenomenon of entanglement has great potential, not least for quantum cryptography. In this respect, QUESS should provide valuable findings on the use and exchange of quantum cryptographic keys over previously unassailable distances. To this end, what are known as quantum keys are created between the broadcast station and the ground stations using photons. Any attempt at eavesdropping during key production would alter the condition of the photons and would thus immediately be noticed due to quantum entanglement.
If this orbital experiment is successful, it will bring the world a step closer to the quantum internet, which promises a new high level of security thanks to quantum cryptographic methods. In order to reach this goal, a new, stable quantum communication network over distances which can only be covered via orbit is needed, as in the case of QUESS.
The value for the future of the pioneering work connected to QUESS can only be guessed. A similar view is held by the Chinese quantum physicists under Jian-Wei Pan, Professor at the University of Science and Technology of China and the Chinese Academy of Sciences, a former doctoral student of Anton Zeilinger’s at the University of Vienna and OeAW member abroad. In his opinion, the project can thus be termed ‘revolutionary’. The successful launch into orbit certainly marks the first step towards this revolution in quantum physics.
emer. o. Univ.- Dr. h.c. Dr. h.c. Anton Zeilinger
Institut für Quantenoptik und Quanteninformation (IQOQI) Wien Österreichische Akademie der Wissenschaften und Quantenoptik, Quantennanophysik und Quanteninformation Universität Wien, Fakultät für PhysikUniversität Wien
1090 - Wien, Boltzmanngasse 3
+43-1-4277-512 01
anton.zeilinger [at] univie.ac (p) at
Dipl.-Soz. Sven Hartwig
Leitung Öffentlichkeit & KommunikationÖsterreichische Akademie der Wissenschaften
1010 - Wien, Dr. Ignaz Seipel-Platz 2
+43 1 51581-13 31
sven.hartwig [at] oeaw.ac (p) at
Mag. Veronika Schallhart
Pressebüro der Universität WienForschung und Lehre
1010 - Wien, Universitätsring 1
+43-1-4277-175 30
+43-664-602 77-175 30
veronika.schallhart [at] univie.ac (p) at
