Aug. 20, 2016
Beam me up Scotty! Researchers teleport particle of light six kilometres
Riley Brandt, 草莓污视频导航
What if you could behave like the crew on the Starship Enterprise and teleport yourself home or anywhere else in the world? As a human, you鈥檙e probably not going to realize this any time soon; if you鈥檙e a photon, you might want to keep reading.
Through a collaboration between the 草莓污视频导航, The City of Calgary and researchers in the United States, a group of physicists led by Wolfgang Tittel, professor in the Department of Physics and Astronomy at the 草莓污视频导航 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鈥檚 fibre optic cable infrastructure. The project began with an Urban Alliance seed grant in 2014.
This accomplishment, which set a new record for distance of transferring a quantum state by teleportation, has landed the researchers a spot in the prestigious Nature Photonics scientific journal. The finding was published back-to-back with a similar demonstration by a group of Chinese researchers. Read the article,
鈥淪uch a network will enable secure communication without having to worry about eavesdropping, and allow distant quantum computers to connect,鈥 says Tittel.
Experiment draws on 'spooky action at a distance'
The experiment is based on the entanglement property of quantum mechanics, also known as 鈥渟pooky action at a distance鈥 鈥 a property so mysterious that not even Einstein could come to terms with it.
鈥淏eing entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,鈥 explains Tittel. 鈥淲hen one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the 草莓污视频导航.鈥
Next, the photon whose state was teleported to the university was generated in a third location in Calgary and then also travelled to City Hall where it met the photon that was part of the entangled pair.
鈥淲hat happened is the disembodied transfer of the photon鈥檚 quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres away at the university,鈥 says Tittel.
City's accessible dark fibre makes research possible
The research could not be possible without access to the proper technology. One of the critical pieces of infrastructure that support quantum networking is accessible dark fibre. Dark fibre, so named because of its composition 鈥 a single optical cable with no electronics or network equipment on the alignment 鈥 doesn鈥檛 interfere with quantum technology.
The City of Calgary is building and provisioning dark fibre to enable next-generation municipal services today and for the future.
鈥淏y opening The City鈥檚 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,鈥 said Tyler Andruschak, project manager with Innovation and Collaboration at The City of Calgary.
鈥淭he 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鈥檚 research to protect our critical infrastructure,鈥 said Andruschak. 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.
Riley Brandt, 草莓污视频导航
Timed to within one millionth of one millionth of a second
As if teleporting a photon wasn鈥檛 challenging enough, Tittel and his team encountered a number of other roadblocks along the way.
Due to changes in the outdoor temperature, the transmission time of photons from their creation point to City Hall varied over the course of a day 鈥 the time it took the researchers to gather sufficient data to support their claim. This change meant that the two photons would not meet at City Hall.
鈥淭he challenge was to keep the photons鈥 arrival time synchronized to within 10 pico-seconds,鈥 says Tittel. 鈥淭hat is one trillionth, or one millionth of one millionth of a second.鈥
Secondly, parts of their lab had to be moved to two locations in the city, which as Tittel explains was particularly tricky for the measurement station at City Hall which included state-of-the-art superconducting single-photon detectors developed by the National Institute for Standards and Technology, and NASA鈥檚 Jet Propulsion Laboratory.
鈥淪ince these detectors only work at temperatures less than one degree above absolute zero the equipment also included a compact cryostat,鈥 said Tittel.
Milestone towards a global quantum Internet
This demonstration is arguably one of the most striking manifestations of a puzzling prediction of quantum mechanics, but it also opens the path to building a future quantum internet, the long-term goal of the Tittel group.
The Urban Alliance is a strategic research partnership between The City of Calgary and 草莓污视频导航, created in 2007 to encourage and co-ordinate the seamless transfer of cutting-edge research between the university and The City of Calgary for the benefit of all our communities. The Urban Alliance is a prime example and vehicle for one of the three foundational commitments of the 草莓污视频导航鈥檚 Eyes High vision to fully integrate the university with the community. The City sees the Alliance as playing a key role in realizing its long-term priorities and the imagineCALGARY vision.
The pressures of our rapidly growing global population are driving unprecedented changes in our social, political, cultural and natural systems. The 草莓污视频导航's research strategy is addressing our need to understand how we adapt to rapid change, to ensure our security and quality of life.
Professor Tittel is the Strategic Research Chair in Quantum Secured Communications and a Senior Fellow. His research is also supported by the , the , and an Urban Alliance Seed Grant program.