Qubit errors traced to two sources, cosmic rays, cooler vibrations

Correlated errors, accounting for an unspecified percentage of errors in superconducting qubits, are now being distinguished as originating from two distinct sources, a surprising finding that moves beyond simply detecting errors to understanding their origins. Researchers at the Massachusetts Institute of Technology have linked these errors to both ionizing radiation from cosmic and terrestrial sources and to mechanical vibrations from the pulse tube within dilution refrigerators. The work presents a method for differentiating these error types by examining their temporal, spatial, and frequency characteristics, potentially enabling targeted error-mitigation strategies. The team also found that engineering the superconducting gap across Josephson junctions reduces the rate of errors from both radiation and vibrations. They measured arrays of qubits with varying superconducting gap differences, where the difference in superconducting gap was less…