Scalable error mitigation for noisy quantum circuits produces competitive expectation values

Abstract

Demonstrating relevant physical quantities in practical size problems on a fully programmable quantum processor is a key milestone for defining a blueprint toward a useful quantum advantage. The current quantum computer is noisy and requires scalable error mitigation techniques for an accurate estimation of the observables. One of the prominent techniques in this front is zero-noise extrapolation (ZNE), however, the practical scaling of this method to a larger system size remains unknown. Here, we present a systematic path toward scalable zero-noise extrapolation technique by exploring quench dynamics of 2D Ising spin lattice using up to 26 qubits. We discuss several additional error suppression strategies to extend the reach of ZNE. Finally, we show that measured observables can surpass an established classical approximate method in the limit of increasing entanglement. This work is based on arXiv:2108.09197.