Welcome!

News Feed Item

Experiment Opens the Door to Multi-Party Quantum Communication

WATERLOO, ON--(Marketwired - March 23, 2014) - In the world of quantum science, Alice and Bob have been talking to one another for years. Charlie joined the conversation a few years ago, but now with spacelike separation, scientists have measured that their communication occurs faster than the speed of light.

For the first time, physicists at the Institute for Quantum Computing (IQC) at the University of Waterloo have demonstrated the distribution of three entangled photons at three different locations (Alice, Bob and Charlie) several hundreds of metres apart, proving quantum nonlocality for more than two entangled photons.

The findings of the experiment, Experimental Three-Particle Quantum Nonlocality under Strict Locality Conditions, are published in Nature Photonics today. 

Once described by Einstein as "spooky action at a distance," this three-photon entanglement leads to interesting possibilities for multi-party quantum communication.

Nonlocality describes the ability of particles to instantaneously know about each other's state, even when separated by large distances. In the quantum world, this means it might be possible to transfer information instantaneously -- faster than the speed of light. This contravenes what Einstein called the "principle of local action," the rule that distant objects cannot have direct influence on one another, and that an object is directly influenced only by its immediate surroundings.

To truly test that the hidden local variables are not responsible for the correlation between the three photons, IQC scientists needed the experiment to close what is known as the locality loophole. They achieved this separation of the entangled photons in a way that did not allow for a signal to coordinate the behaviour of the photons, but beaming the entangled photons to trailers parked in fields several hundred meters from their lab.

"Correlations measured from quantum systems can tell us a lot about nature at the most fundamental level," said co-author Professor Kevin Resch, Canada Research Chair in Optical Quantum Technologies and recent winner of the E.W.R. Steacie Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC). "Three-particle entanglement is more complex than that of pairs. We can exploit the complex behaviour to rule out certain descriptions of nature or as a resource for new quantum technologies."

The project team studied the correlations of three photons in a Greenberger-Horne-Zeilinger (GHZ) state -- a type of entangled quantum state involving at least three particles.

First, photon triplets were generated in Resch's lab -- the Alice in the experiment. Then, the first photon was delayed in a 580m optical fibre in the lab while the two other photons travelled up 85m of optical fibre to the rooftop where they were sent through two telescopes. Both photons were then sent to two trailers, Bob and Charlie, about 700m away from the source and from each other.

To maintain the spacelike separate in the experiment, a fourth party, Randy, located in a third trailer randomly selected each of the measurements that Alice was to perform on her photons in the lab.

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. The UQD time tagging devices also ensured the measurements happened in a very small time window (three nanoseconds), meaning that no information could possibly be transmitted from one location to the other during the measurement period ­-- a critical condition to prove the non-locality of entanglement.

"The idea of entangling three photons has been around for a long time," said Professor Thomas Jennewein, a co-author of the paper. "It took the right people with the right knowledge to come together to make the experiment happen in the short time it did. IQC had the right mix at the right time."

The experiment demonstrated the distribution of three entangled particles, which can eventually be used to do more than pairwise communication where only one party can communicate with another. It opens the possibility for multipartite quantum communication protocols, including Quantum Key Distribution (QKD), third man cryptography and quantum secret sharing.

"The interesting result is that we now have the ability to do more than paired quantum communication," said the paper's lead author Chris Erven, a former IQC PhD student who is now a research assistant at the University of Bristol. "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."

The team from the Institute for Quantum Computing and the Department of Physics and Astronomy in the Faculty of Science at the University of Waterloo included students Chris Erven, Evan Meyer-Scott, Kent Fisher, Jonathan Lavoie, Christopher Pugh, Jean-Paul Bourgoin, Laura Richards, Nickolay Gigov, postdoctoral fellow Brendon Higgins, Professor Jennewein, Professor Resch and Raymond Laflamme, executive director of IQC.

The project team also included former IQC postdoctoral fellows Robert Prevedel, now at the Max F. Perutz Laboratories (MFPL) and the Institute for Molecular Pathology (IMP); Zhizhong Yan, now at Macquarie University; Krister Shalm now at the National Institute of Standards and Technology (NIST); and former faculty member Gregor Weihs, now at the Institut fur Experimentalphysik at the University of Innsbruck.

About the University of Waterloo
In just half a century, the University of Waterloo, located at the heart of Canada's technology hub, has become one of Canada's leading comprehensive universities with 35,000 full- and part-time students in undergraduate and graduate programs. Waterloo, as home to the world's largest post-secondary co-operative education program, embraces its connections to the world and encourages enterprising partnerships in learning, research and discovery. In the next decade, the university is committed to building a better future for Canada and the world by championing innovation and collaboration to create solutions relevant to the needs of today and tomorrow. For more information about Waterloo, please visit www.uwaterloo.ca.

Attention broadcasters: Waterloo has facilities to provide broadcast quality audio and video feeds with a double-ender studio. Please contact us to book.

Image Available: http://www.marketwire.com/library/MwGo/2014/3/23/11G013641/Images/Rooftop-1006400638409.jpg
Image Available: http://www.marketwire.com/library/MwGo/2014/3/23/11G013641/Images/ABCR-335059589703.jpg

More Stories By Marketwired .

Copyright © 2009 Marketwired. All rights reserved. All the news releases provided by Marketwired are copyrighted. Any forms of copying other than an individual user's personal reference without express written permission is prohibited. Further distribution of these materials is strictly forbidden, including but not limited to, posting, emailing, faxing, archiving in a public database, redistributing via a computer network or in a printed form.

Latest Stories
Recognizing the need to identify and validate information security professionals’ competency in securing cloud services, the two leading membership organizations focused on cloud and information security, the Cloud Security Alliance (CSA) and (ISC)^2, joined together to develop an international cloud security credential that reflects the most current and comprehensive best practices for securing and optimizing cloud computing environments.
Companies can harness IoT and predictive analytics to sustain business continuity; predict and manage site performance during emergencies; minimize expensive reactive maintenance; and forecast equipment and maintenance budgets and expenditures. Providing cost-effective, uninterrupted service is challenging, particularly for organizations with geographically dispersed operations.
Sensors and effectors of IoT are solving problems in new ways, but small businesses have been slow to join the quantified world. They’ll need information from IoT using applications as varied as the businesses themselves. In his session at @ThingsExpo, Roger Meike, Distinguished Engineer, Director of Technology Innovation at Intuit, showed how IoT manufacturers can use open standards, public APIs and custom apps to enable the Quantified Small Business. He used a Raspberry Pi to connect sensors...
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Avere delivers a more modern architectural approach to storage that doesn’t require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbuilding of data centers ...
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management...
SYS-CON Events announced today that VAI, a leading ERP software provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. VAI (Vormittag Associates, Inc.) is a leading independent mid-market ERP software developer renowned for its flexible solutions and ability to automate critical business functions for the distribution, manufacturing, specialty retail and service sectors. An IBM Premier Business Part...
In most cases, it is convenient to have some human interaction with a web (micro-)service, no matter how small it is. A traditional approach would be to create an HTTP interface, where user requests will be dispatched and HTML/CSS pages must be served. This approach is indeed very traditional for a web site, but not really convenient for a web service, which is not intended to be good looking, 24x7 up and running and UX-optimized. Instead, talking to a web service in a chat-bot mode would be muc...
It's easy to assume that your app will run on a fast and reliable network. The reality for your app's users, though, is often a slow, unreliable network with spotty coverage. What happens when the network doesn't work, or when the device is in airplane mode? You get unhappy, frustrated users. An offline-first app is an app that works, without error, when there is no network connection.
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, will discuss the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filte...
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
More and more companies are looking to microservices as an architectural pattern for breaking apart applications into more manageable pieces so that agile teams can deliver new features quicker and more effectively. What this pattern has done more than anything to date is spark organizational transformations, setting the foundation for future application development. In practice, however, there are a number of considerations to make that go beyond simply “build, ship, and run,” which changes ho...
SYS-CON Events announced today that AppNeta, the leader in performance insight for business-critical web applications, will exhibit and present at SYS-CON's @DevOpsSummit at Cloud Expo New York, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. AppNeta is the only application performance monitoring (APM) company to provide solutions for all applications – applications you develop internally, business-critical SaaS applications you use and the networks that deli...
Fortunately, meaningful and tangible business cases for IoT are plentiful in a broad array of industries and vertical markets. These range from simple warranty cost reduction for capital intensive assets, to minimizing downtime for vital business tools, to creating feedback loops improving product design, to improving and enhancing enterprise customer experiences. All of these business cases, which will be briefly explored in this session, hinge on cost effectively extracting relevant data from ...
SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies adopt disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advanced analytics, and DevO...
As someone who has been dedicated to automation and Application Release Automation (ARA) technology for almost six years now, one of the most common questions I get asked regards Platform-as-a-Service (PaaS). Specifically, people want to know whether release automation is still needed when a PaaS is in place, and why. Isn't that what a PaaS provides? A solution to the deployment and runtime challenges of an application? Why would anyone using a PaaS then need an automation engine with workflow ...