Reducing qubit energy decay and correlated errors from cosmic rays in quantum processors

摘要

Large algorithms can be run on a quantum computer only if quantum error correction is used to lower logical qubit errors. The energy deposited by cosmic-ray muons produces a quasiparticle “heat” pulse that causes the qubits to decay in energy quickly, with errors correlated in space and time, so that error correction fails. Metal layers comprising normal metal and/or small-gap superconductors channel this energy away from the qubit into benign structures so that qubit performance is not degraded. These structures are designed according to the electron-phonon interactions and constraints from electromagnetic radiation to make large reductions in the induced errors so that error correction works properly.