Extending the computational reach of a noisy superconducting quantum processor

TL;DR

This paper demonstrates an error mitigation protocol on a superconducting quantum processor that enhances computational accuracy without hardware changes, enabling more precise quantum chemistry and magnetism simulations.

Contribution

The study applies an extrapolation-based error mitigation technique to a superconducting quantum processor, improving its computational accuracy without additional hardware.

Findings

Error mitigation improves variational quantum chemistry results

Incoherent error suppression reveals inaccessible accuracies

Protocol enhances capabilities of near-term quantum hardware

Abstract

Quantum computation, a completely different paradigm of computing, benefits from theoretically proven speed-ups for certain problems and opens up the possibility of exactly studying the properties of quantum systems. Yet, because of the inherent fragile nature of the physical computing elements, qubits, achieving quantum advantages over classical computation requires extremely low error rates for qubit operations as well as a significant overhead of physical qubits, in order to realize fault-tolerance via quantum error correction. However, recent theoretical work has shown that the accuracy of computation based off expectation values of quantum observables can be enhanced through an extrapolation of results from a collection of varying noisy experiments. Here, we demonstrate this error mitigation protocol on a superconducting quantum processor, enhancing its computational capability, with no additional hardware modifications. We apply the protocol to mitigate errors on canonical single- and two-qubit experiments and then extend its application to the variational optimization of Hamiltonians for quantum chemistry and magnetism. We effectively demonstrate that the suppression of incoherent errors helps unearth otherwise inaccessible accuracies to the variational solutions using our noisy processor. These results demonstrate that error mitigation techniques will be critical to significantly enhance the capabilities of near-term quantum computing hardware.