SQMS Study Links Qubit Performance to Material and Fabrication Features

Insider Brief

• Researchers from the Fermilab-led SQMS Center identified material and fabrication features associated with variations in superconducting qubit performance.
• The study examined 22 superconducting transmon qubits using seven materials-characterization techniques alongside quantum coherence measurements.
• Researchers identified oxide thickness, etched sidewall angles and trench depth as key features linked to performance differences, with the three factors accounting for up to a twofold variation among the studied qubits.
• This story is based directly on reporting published by Fermilab on the SQMS study.

PRESS RELEASE — Understanding why some superconducting qubits outperform others remains one of the most important challenges in quantum computing. As long as the quantum state in a qubit maintains its coherence and does not decay, information can be held and potentially processed in advanced calculations far beyond the capabilities of current computers.

“Advancing quantum information science is fundamentally tied to our ability to control matter at the atomic level.”

Bindu Nair, U.S. Department of Energy

While over the past decade researchers have identified many possible coherence-limiting defects in the materials used to make the qubits, establishing which microscopic features explain why identically designed qubits may perform differently has remained a challenge. Now, researchers from the Fermi National Accelerator Laboratory-led Superconducting Quantum Materials and Systems Center, or SQMS, have completed one of the most comprehensive studies ever conducted, linking materials and their structures — including surfaces, interfaces and geometries — to variations in quantum device performance. This research provides new insights that directly connect to device fabrication, an important step on the path toward building practical and reliable quantum computers.