US Army-funded research project makes inroads on scaling quantum processors

Andrew Eversden

Correction: An earlier version of this story misspelled the name of Sara Gamble, a program manager in quantum information science at the Army Research Office.

WASHINGTON — A research project funded by the U.S. Army has developed a new approach to manufacturing quantum computer chips, representing a significant step forward toward making quantum processors at the scale needed to deliver rapid processing capabilities to the battlefield.

The new approach could impact how the service builds quantum networks and distributed sensing capabilities.

Quantum processors use a qubit to store information. The researchers were looking to increase the amount of qubits placed onto a photonic chip. Prior to the experiment, researchers were only able to get two or three qubits into one photonic chip, said Sara Gamble, a program manager in quantum information science at the Army Research Office, an element of the Army Research Laboratory at Combat Capabilities Development Command.

“Currently we can exert control and successfully manipulate handfuls of qubits, like very countable numbers of them. But when it comes to the millions or billions of qubits that we need for applications of actual interest, how to get to those millions or billions of qubits is a major research challenge,” Gamble said in an interview with C4ISRNET.

In this study, researchers succeeded in integrating 128 qubits onto a photonic chip by making small quantum “chiplets” and placing them onto a larger circuit. The chiplets were able to carry quantum information through artificial atoms created by scientists by exploiting defects in diamonds.

The increase to 128 is a large jump, but well short of the thousands, millions or billions of qubits needed to successfully complete the applications the service sees as useful in the future. For example, qubits could be used for distributed sensing through networks of quantum systems on the battlefield to allow for greater situational awareness, though Gamble noted that quantum information science research is still in the early stage.

“We know that a lot of these qubit types are also excellent sensors. So for things like electric and magnetic fields, these quantum sensors can sense those fields ... with a higher sensitivity than you can get out of classical sensor,” Gamble said. “And then if you network those quantum sensor systems together, that increase you can get in your signal goes up even more.

“So we need those isolated qubit sensors. But then we also need a way for those qubit sensors to talk to each other over a quantum network.”

Being able to process data at quantum speeds would benefit the military as it seeks to make decisions based on large sets of data coming in from the battlefield in near-real time, and as it moves toward multidomain operations.

“It's a fundamentally different way to gather, process and share information,” Gamble said.

The research was completed by scientists at the Massachusetts Institute of Technology and Sandia National Laboratories.

The new technology still needs to undergo tests to ensure the qubits in the chip can be controlled in a way that would help the Army. Gamble said the research team is also considering how to automate parts of the production process.

“Thinking about how we can automate these processes to make them even more repeatable is going to be exciting,” Gamble said, “and something that's going to be necessary if you really want to do this for, you know, millions to billions of qubits instead of 128.”

https://www.c4isrnet.com/battlefield-tech/it-networks/2020/08/17/us-army-funded-research-project-makes-inroads-on-scaling-quantum-processors/