(NYTimes) Cade Metz, technology correspondent at the venerable New York Times reports on Delft University of Technology in the Netherlands, where a team of physicists has taken a significant step toward this computer network of the future, using a technique called quantum teleportation to send data across three physical locations. Previously, this was possible with only two. IQT-News summarizes Metz’s article.
The new experiment indicates that scientists can stretch a quantum network across an increasingly large number of sites. “We are now building small quantum networks in the lab,” said Ronald Hanson, the Delft physicist who oversees the team. “But the idea is to eventually build a quantum internet.”
Their research, unveiled this week with a paper published in the science journal Nature, demonstrates the power of a phenomenon that Albert Einstein once deemed impossible. Quantum teleportation — what he called “spooky action at a distance” — can transfer information between locations without actually moving the physical matter that holds it.
This technology could profoundly change the way data travels from place to place. It draws on more than a century of research involving quantum mechanics, a field of physics that governs the subatomic realm and behaves unlike anything we experience in our everyday lives.
“This not only means that the quantum computer can solve your problem but also that it does not know what the problem is,” said Tracy Eleanor Northup, a researcher at the University of Innsbruck’s Institute for Experimental Physics who is also exploring quantum teleportation. “It does not work that way today. Google knows what you are running on its servers.”
Quantum information cannot simply be copied and sent across a traditional network because of deoherence. Quantum teleportation provides an alternative. Although it cannot move objects from place to place, it can move information by taking advantage of a quantum property called “entanglement”: A change in the state of one quantum system instantaneously affects the state of another, distant one.
“After entanglement, you can no longer describe these states individually,” Dr. Northup said. “Fundamentally, it is now one system.”
These entangled systems could be electrons, particles of light or other objects. In the Netherlands, Dr. Hanson and his team used what is called a nitrogen vacancy center — a tiny empty space in a synthetic diamond in which electrons can be trapped.
The team built three of these quantum systems, named Alice, Bob and Charlie, and connected them in a line with strands of optical fiber. The scientists could then entangle these systems by sending individual photons — particles of light — between them.
The researchers could then transfer this quantum state to another qubit, a carbon nucleus, inside Bob’s synthetic diamond. Doing so freed up Bob’s electron, and researchers could then entangle it with another electron belonging to Charlie. By performing a specific quantum operation on both of Bob’s qubits — the electron and the carbon nucleus — the researchers could then glue the two entanglements together: Alice plus Bob glued to Bob plus Charlie.
The result: Alice was entangled with Charlie, which allowed data to teleport across all three nodes.
The information also cannot be intercepted. A future quantum internet, powered by quantum teleportation, could provide a new kind of encryption that is theoretically unbreakable.
In the new experiment, the network nodes were not that far apart — only about 60 feet. But previous experiments have shown that quantum systems can be entangled over longer distances. The hope is that, after several more years of research, quantum teleportation will be viable across many miles. “We are now trying to do this outside the lab,” Dr. Hanson said.
(NYTimes) Click here to read complete article.
Sandra K. Helsel, Ph.D. has been researching and reporting on frontier technologies since 1990. She has her Ph.D. from the University of Arizona.