Wednesday, April 23, 2014

A Step Forward in Quantum Routing


The prospect of a quantum Internet has excited physicists for two decades. A quantum Internet will allow the transmission of information around the world with perfect security and make cloud-based quantum computing a reality.

But first, physicists must perfect the technology of quantum routing—the ability to receive and transmit quantum information without destroying it.

That’s a significant challenge. The key is a technique called quantum teleportation, which transmits information from one point to another without it passing through the space in between. This is a routine operation in any decent quantum optics lab but quantum routing—which concatenates the process—is another challenge altogether.

Today, Wolfgang Pfaff at the Kavli Institute of Nanoscience Delft in the Netherlands and a few pals say they’ve take a significant step toward this goal with the first demonstration of diamond teleporters that can act as nodes in a quantum network. “These results establish diamond spin qubits as a prime candidate for the realization of quantum networks for quantum communication and network-based quantum computing,” they say.

The fundamental difficulty in quantum routing is that quantum information is fragile stuff. So quantum teleportation has always involved creating a qubit, teleporting it and then immediately measuring it to check whether teleportation has been successful.

However, the process of measurement destroys quantum information. So an important goal is to create routers that can read and write quantum information without destroying it.

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