Argonne National Lab Testing Quantum Internet.

• Author: Tadjdeh, Yasmin

In a major step forward for quantum technology, the Department of Energy's Argonne National Laboratory and the University of Chicago recently announced they had completed successful tests on what they call a "quantum loop," which serves as a precursor for what may one day be a national quantum internet.

While most are familiar with the zeroes and ones required for digital computing, quantum technology is the manipulation of neutrons, photons, electrons and protons to perform tasks. Scientists say the technology will have major implications across the board.

"We think this is the next wave," said Paul Dabbar, undersecretary for science at the Department of Energy.

Quantum technologies offer the United States three major potential applications, he said during a phone call with reporters. Those include computing, communications and sensing. All will be particularly meaningful for security.

During the quantum loop experiment, Argonne and the University of Chicago--working alongside an industry partner called Qubitekk--built a single photon source of entangled particles that was shot out into an existing fiber network in the Chicago suburbs on separate paths 26 miles in length, said David Awschalom, Argonne's senior scientist who also serves as the quantum information science group leader at the University of Chicago and director of the Chicago Quantum Exchange.

Once the photons returned, scientists studied their measurements to see how robustly they were entangled, he said.

"We want to make sure that those two photons are still entangled," he said. "We measure how carefully they are [entangled] and we're going to extend this from platform-to-platform as the basis for a national network."

The experiment was funded by the Energy Department's office of science.

The quantum loop effort is partially modeled on the Advanced Research Projects Agency Network, or ARPANET--which eventually led to the creation of the internet, Dabbar said.

The Defense Department in 1969 funded the initial four nodes of ARPANET, primarily in California. Over the next two decades, node by node, the internet was created, he said.

"Certainly, we're looking to start building nodes first around Chicago and then around New York and then elsewhere adding universities, labs and the commercial sector... somewhat similar to that," he said.

While ARPANET grew in an ad hoc, grassroots manner, leaders of the initiative are being very deliberate about how a future quantum network can be...