Toward efficient correction of multiqubit measurement errors: pair correlation method

Measurement errors limit the performance of near-term quantum computers and their potential for practical application. However they are partly correctable after a calibration step that requires, for a complete implementation on a register of n qubits, 2(n) additional measurements. Here we introduce an approximate but efficient method for multiqubit measurement error characterization and mitigation requiring the classical processing of 2(n) x 2(n) matrices, but only O(4(k)n(2)) measurements, where k = O(1) is the number of qubits in a correlation volume. We demonstrate and validate the method on an IBM Q processor with registers of 4 and 8 superconducting qubits.

Automated summary

Measurement errors on near-term quantum computers can be partially corrected after a calibration step to improve performance. A new efficient method for multiqubit measurement error characterization and mitigation has been introduced, requiring classical processing of matrices and fewer measurements. This method has been demonstrated and validated on IBM Q processor with 4 and 8 superconducting qubits.