Can radiation-induced error bursts in superconducting chips be made rare enough?

In transmon arrays, ionizing-radiation impacts in the substrate produce phonons that break Cooper pairs and raise the quasiparticle density near Josephson junctions, causing $T1$ drops and frequency shifts over regions of order $\mathrm{cm}^2$ for times of about 1 to 30 ms. Establish the quantitative chain (energy deposition, phonon transport, quasiparticle generation, trapping and recombination) that sets the burst rate and footprint, and determine whether gap engineering, phonon traps and shielding can lower the rate of bursts that defeat a distance-d surface-code patch to the level required for logical error rates near $10^{-12}$ per cycle.

Measured burst rates and footprints versus shielding, junction gap profile and phonon-trap density in large arrays, reproduced by a quantitative microscopic model and fed into logical-error simulations.