Quantum annealing correction for random Ising problems

TL;DR

This paper shows that quantum annealing correction significantly improves the performance of a quantum annealer on hard random Ising problems, addressing errors and device limitations.

Contribution

The study introduces a tailored quantum annealing correction method for the D-Wave Two device, demonstrating performance improvements over classical repetition codes and robustness to device imperfections.

Findings

QAC improves performance with problem size and hardness

QAC overcomes device precision limits and calibration errors

Performance remains robust despite missing qubits

Abstract

We demonstrate that the performance of a quantum annealer on hard random Ising optimization problems can be substantially improved using quantum annealing correction (QAC). Our error correction strategy is tailored to the D-Wave Two device. We find that QAC provides a statistically significant enhancement in the performance of the device over a classical repetition code, improving as a function of problem size as well as hardness. Moreover, QAC provides a mechanism for overcoming the precision limit of the device, in addition to correcting calibration errors. Performance is robust even to missing qubits. We present evidence for a constructive role played by quantum effects in our experiments by contrasting the experimental results with the predictions of a classical model of the device. Our work demonstrates the importance of error correction in appropriately determining the performance of quantum annealers.