Gap engineering reduces errors in superconducting qubits

Researchers from the Massachusetts Institute of Technology and the Johns Hopkins Applied Physics Laboratory observed reduced errors in qubit arrays with a greater difference in superconducting gap energy, suggesting a path toward mitigating a vulnerability in quantum computing technology. The work demonstrates that high-energy particles increase quasiparticle density near Josephson junctions, creating correlated errors that are difficult to correct with standard methods. The researchers found that increasing the degree of gap engineering at the Josephson junction lessened the severity of correlated errors. The severity of errors in transmon qubit arrays diminished with increased differences in superconducting gap energy at the Josephson junction, a finding that addresses a persistent challenge in building stable quantum computers. Researchers exposed arrays to alpha particles from an americium-241 source and electrons from a pulsed linear accelerator to assess the impact of radiation on qubit performance. Observations of temporally and spatially correlated errors supported the hypothesis that hadronic cosmic…