Bardin Helps Google Design a Low-Power Controller to be Used with Quantum Computers

The wiring on Bristlecone is one of Google's flagship cryostats.
The wiring on Bristlecone is one of Google's flagship cryostats. (Image credit: Google)

Joseph C. Bardin, associate professor of electrical and computer engineering, has helped scientists at Google design and build a small, low-power controller to be used with quantum computers – devices that operate at near absolute zero to take advantage of physical phenomena that only occur at those temperatures. Bardin, along with Erik Lucero, staff research scientist and hardware lead for the Google AI Quantum Team, described the new devices on Google’s AI Blog in a Feb. 21 post

They say the new controller shows they have made significant progress toward an efficient, reliable and scalable means of controlling quantum systems’ electronics — systems scientists hope will someday solve computationally complex problems beyond the reach of classical machines.

At the International Solid State Circuits Conference (ISSCC) in San Francisco last week, Bardin and researchers on the company’s (artificial intelligence) AI Quantum team unveiled a cryogenic controller fabricated using CMOS – conventional computer chip technology. Google says the 1-millimeter-by-1.6-millimeter controller — which provides an instruction set for single-qubit operations — runs at 3 degrees Kelvin (about -454.27 degrees Fahrenheit) and consumes less than 2 milliwatts of power — 1,000 times less power than Google’s current control electronics. A qubit is the basic unit of quantum information.

Bardin says the new controller is a first step in steamlining the complex network of technology needed to connect the quantum computing element with traditional computers that operate at room temperature. The new custom integrated circuits, by contrast, control qubits, the basic units of quantum information, from within the cooling system, reducing the number of physical connections needed to and from quantum processors. According to Google, baseline experiments for the controller hardware show “similar” performance compared with its standard qubit control electronics.

Bardin and Erik Lucero caution that it’s merely a first step toward a “truly scalable” qubit management system — the controller only addresses a single qubit, and it still requires several connections to room temperature. Still, they say it’s promising progress in the pursuit of reducing the energy required to control qubits while maintaining the control required to perform “high-quality” qubit operations.