Fermilab study reveals root causes of qubit variability

A Fermilab-led team has pinpointed nanoscale material flaws behind inconsistent performance in superconducting transmon qubits. Using double-blind analysis across 22 devices, they found that tiny changes—like nanometer shifts in oxide thickness and trench depths—can double or halve how long a qubit stays stable. Industry partner Rigetti Computing is now tweaking fabrication based on these results, aiming for more reliable quantum chips.

• Double-blind study across 22 transmon qubits
• Single-nanometer oxide changes linked to twofold T1 variation
• Sub-20nm trench depths also impact stability
• Macroscopic defects found less significant
• Rigetti already applying findings to chip process