Quantum leaps and bounds
Advances in the so-called quantum Internet are moving at light speed, including a quantum information storage device developed at the University of Calgary.
Researchers in the University of Calgary's Faculty of Science have made important advances to support the imminent deployment of the quantum Internet — an infallibly secure, powerful and rapid information vehicle that could soon revolutionize how we share and store highly sensitive data such as banking, medical and confidential government information.
Led by Wolfgang Tittel, professor of physics and astronomy, the team developed the first-ever atomic storage device for quantum data that is compatible with standard optical fibre and can operate with telecommunication-wavelength photons.
The research, which was recently published in Nature Photonics, was co-authored by University of Calgary postdoctoral fellows and PhD students Erhan Saglamyurek, Jeongwan Jin, and Daniel Oblak and developed in partnership with scientists Varun B. Verma, Matthew D. Shaw, Francesco Marsili and Sae Woo Nam from the National Institute of Standards and Technology in the U.S. and the Jet Propulsion Laboratory.
The team’s research demonstrates the potential to leverage existing and traditional fibre optic infrastructure to transmit highly secure quantum information.
“We anticipate that our newly designed system will soon be employed as a component of optical quantum computers or as an atomic processing element for advanced quantum photonic applications," says Tittel, the Alberta Innovates Technology Futures Strategic Research Chair in Quantum Secured Communication.
Security drives development of quantum Internet
Our contemporary information society has been driven by powerful and constantly evolving technologies that allow digital information to be processed, stored and transmitted.
In recent years, growing concerns surrounding our reliance on the existing infrastructure and significant communication security gaps have led scientists to turn to more sophisticated technologies such as quantum information technology (QIT) to resolve those problems.
QIT has been a solution of choice to tackle these important societal problems because it leverages the unique and often counterintuitive features of quantum mechanics — a theory that describes the behaviour of very small particles such as atoms, electrons, and elementary particles of light known as photons.
“Some of the most important applications of QIT are quantum computers with unprecedented computational power, quantum cryptography allowing unbreakable secret communication, and quantum metrology enabling measurement devices with ultimate levels of precision,” explains Tittel, a world expert on quantum communication, cryptography and memory who is also a member of the University of Calgary’s Institute for Quantum Science and Technology.
Intrinsic challenges associated with qit deployment
As in the case of classical information technologies, the utilization of QIT requires potentially distant parties to process, store and distribute quantum information in what has been coined the quantum Internet.
The fragile nature of quantum information has made it an outstanding challenge to develop the quantum hardware and novel architecture that would allow the broad deployment of the quantum Internet.
Over the past 10 years, global efforts to develop quantum memory for a future quantum Internet have led to important progress and development of highly complex prototype devices based on atomic systems.
“It’s been a longstanding problem that these technologies are incompatible with the wavelength of light employed in widely used and readily available fibre-optic networks,” says Erhan Saglamyurek, a postdoctoral fellow in the Department of Physics and Astronomy. “Another problem is that none of these atomic devices, which are typically in bulky structures, can be physically confined into a fibre cable, which can be very long and as as thin as a human hair,” he adds.
New study overcomes major QIT challenges
In its recent study, the research team showed that these major obstacles to building a quantum Internet could be overcome.
“Our research demonstrated the possibility of storing photons at telecommunication wavelength in a commercially available erbium-doped fibre, which is exactly the building block of fibre amplifiers in current communication networks,” says Jeongwan Jin, who was a PhD student in professor Tittel’s group.
“Instead of employing the billions of erbium atoms contained in the fibre for amplification, we used them for storing quantum light,” adds postdoctoral fellow Daniel Oblak. “We cooled the fibre down to a temperature close to absolute zero where the erbium atoms behave very orderly and we programmed the erbium atoms in such a way that telecom-wavelength photons are stored and retrieved in our fibre quantum memory after a pre-programmed delay.”
Remaining gaps for the mass usage of QIT
Despite these important advances, Tittel concedes that a lot of work remains to move from a proof-of-principle demonstration to a fully practical implementation of QIT within our existing fibre optic infrastructure.
“The storage efficiency and storage times achieved in our research are limited and need to be substantially improved,” says Tittel, who hopes his team’s contribution will spark more research into this direction. “The good news is that a future quantum Internet is one step closer to reality,” he concludes.
This project was funded by Alberta Innovates Technology Futures, Alberta Innovation and Advanced Education, the National Science and Engineering Research Council of Canada, the Canadian Institute for Advanced Research, Canada Foundation for Innovation, the U.S. Defense Advanced Research Projects Agency, and the U.S. National Aeronautics and Space Administration.