Active Readout Error Mitigation

TL;DR

This paper introduces an active readout error mitigation technique for quantum computers that encodes qubits into multi-qubit states before measurement, significantly reducing errors with minimal resource overhead.

Contribution

The authors propose a novel active error mitigation scheme that encodes qubits into multi-qubit states immediately before readout, independent of circuit depth and compatible with current hardware.

Findings

Achieved 80% reduction in readout errors on IBMQ Mumbai

Demonstrated compatibility with existing hardware error rates

Analyzed effectiveness using two types of error-correcting codes

Abstract

Mitigating errors is a significant challenge for near term quantum computers. One of the most important sources of errors is related to the readout of the quantum state into a classical bit stream. A variety of techniques have been proposed to mitigate these errors with post-hoc corrections. We propose a complementary scheme to actively reduce readout errors on a shot-by-shot basis by encoding single qubits, immediately prior to readout, into multi-qubit states. The computational resources of our technique are independent of the circuit depth and fully compatible with current hardware error rates and connectivity. We analyze the potential of our approach using two types of error-correcting codes and, as a proof of principle, demonstrate an 80% improvement in readout error on the IBMQ Mumbai quantum computer.