论文标题
用于近似图形着色的混合量子古典算法
Hybrid quantum-classical algorithms for approximate graph coloring
论文作者
论文摘要
我们展示了如何将递归量子近似优化算法(RQAOA)应用于最大$ K $ -CUT,这是找到图形的大约$ k $ vertex着色的问题。我们将此提案与最著名的古典和混合古典量子算法进行比较。首先,我们表明,标准(非恢复)QAOA无法在任何恒定级别$ p $上为大多数常规的两部分图求解此优化问题:QAOA所达到的近似值比随机分配颜色要好得多。其次,我们构建了一种有效的经典模拟算法,该算法模拟级别-1 $ QAOA和级别-1 $ rqaoa用于任意图。特别是,这些混合算法产生了有效的经典算法,并且预期使用量子力学不会产生任何好处。 Nevertheless, they provide a suitable testbed for assessing the potential benefit of hybrid algorithm: We use the simulation algorithm to perform large-scale simulation of level-$1$ QAOA and RQAOA with up to $300$ qutrits applied to ensembles of randomly generated $3$-colorable constant-degree graphs.我们发现水平为$ 1 $ rqaoa具有令人惊讶的竞争力:对于所考虑的合奏,其近似值通常高于基于舍入SDP放松的最著名的通用古典算法所实现的比率。这表明高级RQAOA可能是NISQ设备的潜在有用算法的有趣可能性。
We show how to apply the recursive quantum approximate optimization algorithm (RQAOA) to MAX-$k$-CUT, the problem of finding an approximate $k$-vertex coloring of a graph. We compare this proposal to the best known classical and hybrid classical-quantum algorithms. First, we show that the standard (non-recursive) QAOA fails to solve this optimization problem for most regular bipartite graphs at any constant level $p$: the approximation ratio achieved by QAOA is hardly better than assigning colors to vertices at random. Second, we construct an efficient classical simulation algorithm which simulates level-$1$ QAOA and level-$1$ RQAOA for arbitrary graphs. In particular, these hybrid algorithms give rise to efficient classical algorithms, and no benefit arising from the use of quantum mechanics is to be expected. Nevertheless, they provide a suitable testbed for assessing the potential benefit of hybrid algorithm: We use the simulation algorithm to perform large-scale simulation of level-$1$ QAOA and RQAOA with up to $300$ qutrits applied to ensembles of randomly generated $3$-colorable constant-degree graphs. We find that level-$1$ RQAOA is surprisingly competitive: for the ensembles considered, its approximation ratios are often higher than those achieved by the best known generic classical algorithm based on rounding an SDP relaxation. This suggests the intriguing possibility that higher-level RQAOA may be a potentially useful algorithm for NISQ devices.