Last month, PACE reported on China’s launch of the world’s first quantum satellite, which is on a two-year mission to establish encrypted communications. This week, a group of physicists from the University of Calgary in Canada have made an important step towards quantum communications by setting a new record for distance of transferring a quantum state by teleportation.
Through a collaboration between the University of Calgary, The City of Calgary and researchers in the United States, a group of physicists led by Wolfgang Tittel (a professor of physics and astronomy at the University of Calgary) have successfully demonstrated teleportation of a photon (an elementary particle of light) over a straight-line distance of six kilometres using the City of Calgary’s fibre optic cable infrastructure.
“Such a network will enable secure communication without having to worry about eavesdropping, and allow distant quantum computers to connect,” said Tittel.
The experiment is based on the entanglement property of quantum mechanics, also known as “spooky action at a distance”.
“Being entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,” said Tittel.
In the experiment, when one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the University of Calgary. The photon whose state was teleported to the university was generated in a third location in Calgary, before travelling to City Hall where it met the photon that was part of the entangled pair.
“What happened is the disembodied transfer of the photon’s quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres away at the university,” said Tittel.
Critical to the physicists’ research was the use of dark fibre. Dark fibre is a single optical cable with no electronics or network equipment on the alignment, which means it does not interfere with quantum technology. The City of Calgary is building and provisioning dark fibre to allow next-generation municipal services today and in the future.
“By opening the city’s dark fibre infrastructure to the private and public sector, non-profit companies, and academia, we help enable the development of projects like quantum encryption and create opportunities for further research, innovation and economic growth in Calgary,” said Tyler Andruschak, project manager of innovation and collaboration at The City of Calgary.
Source: University of Calgary