QuFI: a Quantum Fault Injector to Measure the Reliability of Qubits and
  Quantum Circuits
Quantum computing is a new technology that is expected to revolutionize the
computation paradigm in the next few years. Qubits exploit the quantum physics
proprieties to increase the parallelism and speed of computation.
Unfortunately, besides being intrinsically noisy, qubits have also been shown
to be highly susceptible to external sources of faults, such as ionizing
radiation. The latest discoveries highlight a much higher radiation sensitivity
of qubits than traditional transistors and identify a much more complex fault
model than bit-flip. We propose a framework to identify the quantum circuits
sensitivity to radiation-induced faults and the probability for a fault in a
qubit to propagate to the output. Based on the latest studies and radiation
experiments performed on real quantum machines, we model the transient faults
in a qubit as a phase shift with a parametrized magnitude. Additionally, our
framework can inject multiple qubit faults, tuning the phase shift magnitude
based on the proximity of the qubit to the particle strike location. As we show
in the paper, the proposed fault injector is highly flexible, and it can be
used on both quantum circuit simulators and real quantum machines. We report
the finding of more than 285M injections on the Qiskit simulator and 53K
injections on real IBM machines. We consider three quantum algorithms and
identify the faults and qubits that are more likely to impact the output. We
also consider the fault propagation dependence on the circuit scale, showing
that the reliability profile for some quantum algorithms is scale-dependent,
with increased impact from radiation-induced faults as we increase the number
of qubits. Finally, we also consider multi qubits faults, showing that they are
much more critical than single faults. The fault injector and the data
presented in this paper are available in a public repository to allow further
analysis.
Daniel Oliveira Edoardo Giusto Emanuele Dri Nadir Casciola Betis Baheri Qiang Guan Bartolomeo Montrucchio Paolo Rech