Performance of two different quantum annealing correction codes

TL;DR

This paper experimentally compares two quantum annealing correction codes using different processors, revealing a tradeoff between encoded connectivity and performance driven by energy boost effects.

Contribution

It provides the first experimental comparison of two quantum annealing correction codes, highlighting how energy boost influences performance and the connectivity-performance tradeoff.

Findings

Higher success probability with lower temperature processor

Performance differences linked to energy boost from logical operators

Tradeoff identified between encoded connectivity and performance

Abstract

Quantum annealing is a promising approach for solving optimization problems, but like all other quantum information processing methods, it requires error correction to ensure scalability. In this work we experimentally compare two quantum annealing correction codes in the setting of antiferromagnetic chains, using two different quantum annealing processors. The lower temperature processor gives rise to higher success probabilities. The two codes differ in a number of interesting and important ways, but both require four physical qubits per encoded qubit. We find significant performance differences, which we explain in terms of the effective energy boost provided by the respective redundantly encoded logical operators of the two codes. The code with the higher energy boost results in improved performance, at the expense of a lower degree encoded graph. Therefore, we find that there exists an important tradeoff between encoded connectivity and performance for quantum annealing correction codes.