The first experiment of wireless quantum communications in Portugal was carried out at Técnico, this July 8th, by researchers from Instituto de Telecomunicações (IT), covering a distance of 180 meters, which is something unique and will allow Portugal to participate in future space quantum communications.
Professor Carole Mundell, chief scientific adviser at the Foreign and Commonwealth Office, Christopher Sainty, British Ambassador in Portugal, professor Jürgen Mlynek, chair of the Quantum Flagship Advisory Board, professor Arlindo Oliveira, president of Técnico, professor Carlos Salema, president of Instituto de Telecomunicações (IT) and professor Luís Oliveira e Silva, president of IST Scientific council attended the experiment.
José Jesus, Integrated MSc student in Engineering Physics and scholar of the Gulbenkian Programme New Talents in Quantum Technologies, and professor Manfred Niehus, IT researcher and professor at ISEL, led the experience.
“Portugal has been working in this area in recent years and this experiment is an important step”, explained professor Yasser Omar, coordinator of the Physics of Information and Quantum Technologies Group at IT.
Professor Manfred Niehus stressed the importance of the work carried out so far for the success of this experiment. “What we are going to do today is a comprehensive engineering work and a highly interdisciplinary research work. It took us many hours of work and a lot of knowledge”, he stressed.
Satellite communications are currently the solution for transmitting quantum-encrypted messages over long distances. Everything is processed in an apparently simple way: individual light particles, called photons, are sent to encode the quantum bits. These encrypted quantum bits, or qubits, will allow a quantum key distribution. “Quantum technologies allow a symmetric key distribution, thus enabling the sender and the recipient to use the same key to encrypt and decrypt”, explained professor Yasser Omar. “A few years ago no one believed that this was possible, it was pure science fiction”, said the British ambassador.
The cryptographic key is a random sequence of zeros and ones that can be both in horizontal and vertical at the same time. The message is distributed using photons, in a safe way, ensuring that the sender and the receiver can generate the same sequence of zeros and ones.
After getting everything ready, José Jesus launches the key. “Done!”, he shared. The message was successfully received. “We have generated a key that was read and received on the other side. Now we must put the keys together”, explained José Jesus.
This successful experiment was repeated last Wednesday, July 10th, before the closing session of “Ciência’19”, by invitation of the Portuguese Minister for Science, Technology and Higher Education, Manuel Heitor. This second experiment allowed checking the portability of the equipment and technology outside the laboratory. “These two historical moments show that Portugal is able to develop wireless quantum communications, thus ensuring a stronger presence on the international scene, namely in this scientific area”, said professor Yasser Omar.