Researchers from the University of Calgary, Canada, teleported the state of a photon (particle of light) over a six kilometer distance through a “dark fiber” cable. The accomplishment set a new record in quantum teleportation, getting us a little closer to having quantum networks, and ultimately a quantum internet.
Rise Of Quantum Systems
Over the past few years, research into quantum computers and quantum networks has increased as more academics and technology companies began to believe that we may be close to figuring out just how to make these systems work, and then use them outside of the lab.
We’ve had D-Wave announce a more specialized type of quantum computer, and upgrading it every few years. More recently, we’ve had IBM and Google announce their working universal quantum computers. We’ve also had research that showed quantum computers could be built on silicon (as opposed to more expensive materials). Even the NSA has begun warning that the day when quantum computers will break existing forms of encryption is sooner than we think.
Quantum networks are a somewhat different area of research, but still relevant to the quantum field as a whole. If we can teleport information, we may be able to drastically increase the amount of information we can send through networks, and the speed at which we send it, too.
A quantum internet would be beneficial to quantum computers in the same way our regular internet is beneficial to traditional computers. Quantum networks could also aid in protecting communications against eavesdropping, although the jury is still out on how effective that would actually be.
The experiment done by the researchers from the University of Calgary involves using quantum “entanglement,” a process they explain below:
“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,” explained Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary and leader of the project.“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 then generated in a third location in Calgary, and then it also traveled to the City Hall, where it met the photon that was part of the entanglement pair.“What happened is the instantaneous and 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.
Tittel’s group had to overcome some significant challenges along the way. One of the main issues concerned how the variable temperature outside would change when the photons would arrive at City Hall. The two photons were eventually timed to arrive within 10 picoseconds of each other, which is one trillionth--that is, one millionth of one millionth--of a second.
Towards A Global Quantum Internet
The long-term goal of the Tittel group is to create the basic building blocks for a global quantum internet. The City of Calgary will aid in this task by offering access to “dark fiber,” which got its name from its composition; it’s a single optical cable with no electronics or equipment to interfere with the quantum technology.
"By opening The City’s dark fiber 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 with Innovation and Collaboration at The City of Calgary.“The university receives secure access to a small portion of our fibre optic infrastructure and The City may benefit in the future by leveraging the secure encryption keys generated out of the lab’s research to protect our critical infrastructure. In order to deliver next-generation services to Calgarians, The City has been increasing its fibre optic footprint, connecting all City buildings, facilities and assets,” added Andruschak.