Atmospheric Neutron-Induced Fault Generation and Propagation in Quantum Bits and Quantum Circuits

Quantum computing (QC), by exploiting the quantum properties of quantum bits (qubits), significantly improves the performance and efficiency of computation. Unfortunately, quantum devices are very susceptible to external perturbation, including natural radiation. In this article, we measure, through GEANT4 simulations, the charge deposited by impinging neutrons in superconducting quantum devices. As we show, most atmospheric neutrons deposit sufficient energy to break the Cooper pairs and, thus, can potentially modify the qubit state. Then, with a dedicated circuit-level fault injector, we track the transient fault propagation in real quantum circuits and measure its impact on the output probabilities distribution. We discuss the fault model for qubits and show how to measure faults’ impact on the circuit output.