Feeds

EXPOSED: bizarre quantum sibling LOVE TRIANGLE

Bob and Alice get jiggy with Charlie while Randy plays voyeur

Business security measures using SSL

University of Waterloo boffins have demonstrated a three-way quantum entanglement that shows quantum non-locality can work with more than two particles.*

The regulars of quantum physics, Bob and Alice, and the interloper Charlie, had an appropriately trailer-trash setting, but alas saw precious little one-on-one photon action since they were separated by hundreds of metres.

The details of the experiment are straightforward enough. To test the three-way “Greenberger-Horne-Zeilinger” (GHZ) state, the researchers started by generating photon triplets in a lab. The triplets were then split up: the first was sent through a 580m optical fibre to delay it; the other two were sent to two trailers (Bob and Charlie) that are 700m distant from both the source and from each other.

Randy, the fourth party in the experiment and located in yet another trailer, randomly selected the measurements Alice (the originating lab) would perform on her photons.

The university's release describes the setup in each location: “Each trailer contained detectors, time-tagging devices developed by IQC spin off company Universal Quantum Devices (UQD), and quantum random number generators. To ensure the locality loophole was closed, the random number generators determined how the photon at each trailer would be measured independently.”

By keeping the time window small – less than three nanoseconds – the university says the experiment can rule out any information transfer between the three locations, “a critical condition to prove the non-locality of entanglement.”

Chris Everen, lead author of the University of Waterloo group's paper in Nature Photonics (abstract here) and now a research assistant at the University of Bristol, says the result means groups of people could create quantum-secured networks rather than simple one-on-one pairings:

“QKD, so far, has been a pairwise system – meaning that it works best and with less assumptions when you’re only talking with one other person. This is the first experiment where you can now imagine a network of people connected in different ways using the correlations between three or more photons,” he said. ®

Bootnote: The author has corrected the first paragraph, which originally referred to faster-than-light entanglement. This was drawn from early wire releases such as this. However, the Waterloo University release focuses on nonlocality.

The Register notes that researchers in China last year claimed that entanglement appears to operate at speeds faster than light. ®

Providing a secure and efficient Helpdesk

More from The Register

next story
SCREW YOU, Russia! NASA lobs $6.8bn at Boeing AND SpaceX to run space station taxis
Musk charging nearly half as much as Boeing for crew trips
PORTAL TO ELSEWHERE scried in small galaxy far, far away
Supermassive black hole dominates titchy star formation
Boffins say they've got Lithium batteries the wrong way around
Surprises at the nano-scale mean our ideas about how they charge could be all wrong
Edge Research Lab to tackle chilly LOHAN's final test flight
Our US allies to probe potential Vulture 2 servo freeze
Europe prepares to INVADE comet: Rosetta landing site chosen
No word yet on whether backup site is labelled 'K'
Cracked it - Vulture 2 power podule fires servos for 4 HOURS
Pixhawk avionics juice issue sorted, onwards to Spaceport America
City hidden beneath England's Stonehenge had HUMAN ABATTOIR. And a pub
Boozed-up ancients drank beer before tearing corpses apart
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
Protecting users from Firesheep and other Sidejacking attacks with SSL
Discussing the vulnerabilities inherent in Wi-Fi networks, and how using TLS/SSL for your entire site will assure security.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.