Physicists at the University of Vienna and the Austrian Academy of Sciences have achieved quantum teleportation over a record distance of 143 km. The experiment is a major step towards satellite-based quantum communication. The results have now been published in "Nature" (Advance Online Publication/AOP).
An international team led by the Austrian physicist Anton Zeilinger has successfully transmitted quantum states between the two Canary Islands of La Palma and Tenerife, over a distance of 143 km. The previous record, set by researchers in China just a few months ago, was 97 km.
Breaking the distance record wasn't the scientists' primary goal though. This experiment provides the basis for a worldwide information network, in which quantum mechanical effects enable the exchange of messages with greater security, and allow certain calculations to be performed more efficiently than with conventional technologies. In such a future 'quantum internet', quantum teleportation will be a key protocol for the transmission of information between quantum computers.
In a quantum teleportation experiment, quantum states — but not matter — are exchanged between two parties over distances that can be, in principle, arbitrarily long. The process works even if the location of the recipient is not known. Such an exchange can be used either for the transmission of messages, or as an operation in future quantum computers. In these applications the photons that encode the quantum states have to be transported reliably over long distances without compromising the fragile quantum state. The experiment of the Austrian physicists, in which they have now set up a quantum connection suitable for quantum teleportation over distances of more than 100 km, opens up new horizons.
Xiao-song Ma, one of the scientists involved in the experiment, says: "The realization of quantum teleportation over a distance of 143 km has been a huge technological challenge." The photons had to be sent directly through the turbulent atmosphere between the two islands. The use of optical fibres is not suitable for teleportation experiments over such great distances, as signal loss would be too severe. To reach their goal, the scientists had to implement a series of technical innovations. Support came from a theory group at the Max Planck Institute for Quantum Optics in Garching (Germany) and an experimental group at the University of Waterloo (Canada). Ma also said "An important step for our successful teleportation was a method known as 'active feed-forward', which we have used for the first time in a long-distance experiment. It helped us to double the transfer rate". In an active feed-forward protocol, conventional data is sent alongside the quantum information, enabling the recipient to decipher the transferred signal with a higher efficiency.
"Our experiment shows how mature 'quantum technologies' are today, and how useful they can be for practical applications," says Anton Zeilinger. "The next step is satellite-based quantum teleportation, which should enable quantum communication on a global scale. We have now taken a major step in this direction and will use our know-how in an international cooperation, which involves our colleagues at the Chinese Academy of Sciences. The goal is to launch a 'quantum satellite mission'."
Rupert Ursin, who has been working with Zeilinger on long-distance experiments since 2002, adds: "Our latest results are very encouraging with a view to future experiments in which we either exchange signals between Earth and satellites or send messages from one satellite to another." Satellites in 'low-Earth orbit' fly between 200 and 1200 km above the surface of the Earth. (The International Space Station, for example, orbits at an altitude of about 400 km.) "On the way through the atmosphere from La Palma to Tenerife, our signals have been attenuated by a factor of roughly one thousand. Nevertheless, we managed to perform a quantum teleportation experiment. In satellite-based experiments, the distances to be travelled are longer, but the signal will have to pass through less atmosphere. We have now created a sound basis for such experiments."
University of Vienna: http://www.univie.ac.at/en/
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
NASA aims to continue their space exploration with their Asteroid Redirect Mission.
Comets are like movie stars—always more glamorous with their makeup on. A new spacecraft is about orbit and land on what might be the homeliest one ever
Human eyes don't know half of what they're missing. But the Chandra Observatory, with its x-ray vision, gives us a stunning peek.
Astronomers in the US have discovered a distant world with the longest year of any planet outside our Solar System.
The Gaia satellite is being hit by far more micrometeoroids than anticipated, which might spell trouble for spacecraft headed to the same orbital position
On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first two people to land on the lunar surface, while their third crew member, Michael Collins, continued to orbit around the moon. Armstrong and Aldrin arrived in the Lunar Module (LM) Eagle, one of three parts of the Apollo 11 spacecraft which also included…
When scientists looked over the images sent from the Rosetta probe, they found something completely unexpected about its destination
It took 16 years and data from four orbiting spacecraft to assemble, but the U.S. Geological Survey’s new map of Mars is awesome. In beautiful color and excellent detail, the map shows the geology of the Red Planet’s surface today, and reveals a new understanding of its past.
Overcoming two months of delays, a Space Exploration Technologies’ Falcon 9 rocket blasted off from Florida on Monday to put six small commercial communications satellites into orbit for ORBCOMM Inc.
A new study makes it possible for you to hold one of astronomy's great mysteries in your hands—and understand it better too