Rare open-access quantum computer now operational

By Troy Rummler

Photography By Bret Latter

Friday, March 12, 2021

Scientists worldwide can use ion-based testbed

Sandia physicist Susan Clark
QUANTUM FOR ALL — Sandia physicist Susan Clark leads the team that built the Quantum Scientific Computing Open User Testbed. The ion-based quantum computer was made for outside researchers to use.

A new DOE open-access quantum computing testbed is ready for the public. Scientists from Indiana University recently became the first team to begin using Sandia’s Quantum Scientific Computing Open User Testbed, or QSCOUT.

Quantum computers are poised to become major technological drivers over the coming decades. But to get there, scientists need to experiment with quantum machines that relatively few universities or companies have. Now, scientists can use Sandia’s QSCOUT for research that might not be possible at their home institutions, without the cost or restrictions of using a commercial testbed.

“QSCOUT serves a need in the quan­tum community by giving users the con­trols to study the machine itself, which aren’t yet available in commercial quan­tum computing systems. It also saves the­orists and scientists from the trouble of building their own machines. We hope to gain new insights into quantum perfor­mance and architecture as well as solve problems that require quantum computa­tion,” said Sandia physicist and QSCOUT lead Susan Clark.

She said the new testbed is a rare machine in three ways: first, as a free, open-access testbed; second, as one made with trapped ion technology; and third, as a platform that gives users an uncommon amount of control over their research.

Last month, Sandia began running the testbed’s first user experiment for scien­tists from Indiana University. Researchers from IBM, Oak Ridge National Laboratory, the University of New Mexico and the University of California, Berkeley, also have been selected to begin experiments soon. Their projects range from testing benchmark­ing techniques to developing algorithms that could someday solve problems in chemistry too complex for normal computers.

Make a proposal

Now, Sandia is calling for more research proposals. Anyone in the world can sub­mit a proposal to use QSCOUT, and com­puting time is free thanks to funding from the DOE Office of Science, Advanced Scientific Computing Research program. The next group of projects is expected to be selected in the spring.

On top of providing an exceptional research opportunity, QSCOUT has a rare design for a testbed. Most commercial test­beds use technology called superconduct­ing circuits. Such machines need to be kept at ultralow temperatures, making them expensive to build and operate. But Sandia’s testbed uses what is called an ion trap instead. This means Sandia’s testbed can run at warmer temperatures. Trapped ions also yield clearer signals than circuits and hold on to information longer, enabling scientists to perform different types of experiments and compare the two platforms.

Trapped ions are held inside QSCOUT in a so-called “trap on a chip,” a flat, bow tie-shaped device, about 2 cm (0.8 inches) long, overlaid on a semiconductor chip. Three electrically charged atoms of the element ytterbium are suspended in place by radio waves and an electric field above a hair­line channel that runs down the center of the device. Lasers encode information in each ion as a qubit, comparable to a bit in a con­ventional computer, to perform calculations.

Sandia plans to expand the system from three to 32 qubits over the next three years so scientists can perform more sophisti­cated tests.

QSCOUT resides at Sandia’s Microsystems Engineering, Science, and Applications complex, which also pro­duces microelectronics for the nation’s nuclear stockpile.