Measurement Error Mitigation in Quantum Computers Through Classical
  Bit-Flip Correction
We develop a classical bit-flip correction method to mitigate measurement
errors on quantum computers. This method can be applied to any operator, any
number of qubits, and any realistic bit-flip probability. We first demonstrate
the successful performance of this method by correcting the noisy measurements
of the ground-state energy of the longitudinal Ising model. We then generalize
our results to arbitrary operators and test our method both numerically and
experimentally on IBM quantum hardware. As a result, our correction method
reduces the measurement error on the quantum hardware by up to one order of
magnitude. We finally discuss how to pre-process the method and extend it to
other errors sources beyond measurement errors. For local Hamiltonians, the
overhead costs are polynomial in the number of qubits, even if multi-qubit
correlations are included.
Lena Funcke Tobias Hartung Karl Jansen Stefan Kühn Paolo Stornati Xiaoyang Wang