论文标题
通过量子隧道步行进行非凸的量子加速
On Quantum Speedups for Nonconvex Optimization via Quantum Tunneling Walks
论文作者
论文摘要
经典算法通常无效地解决了当地最小值被高壁垒分开的非凸优化问题。在本文中，我们通过利用量子隧道的全局效应来探讨非凸优化的量子加速。具体而言，我们引入了一种称为量子隧道步行（QTW）的量子算法，并将其应用于局部最小值大约全局最小值的非凸问题。我们表明，当不同局部最小值较高但薄且最小值平坦时，QTW在经典随机梯度下降（SGD）上实现了量子加速。基于此观察结果，我们构建了一个特定的双孔景观，其中经典算法无法有效地击中一个目标，但是QTW可以在已知井附近的适当初始状态时可以很好地了解另一个目标。最后，我们通过数值实验证实了我们的发现。
Classical algorithms are often not effective for solving nonconvex optimization problems where local minima are separated by high barriers. In this paper, we explore possible quantum speedups for nonconvex optimization by leveraging the global effect of quantum tunneling. Specifically, we introduce a quantum algorithm termed the quantum tunneling walk (QTW) and apply it to nonconvex problems where local minima are approximately global minima. We show that QTW achieves quantum speedup over classical stochastic gradient descents (SGD) when the barriers between different local minima are high but thin and the minima are flat. Based on this observation, we construct a specific double-well landscape, where classical algorithms cannot efficiently hit one target well knowing the other well but QTW can when given proper initial states near the known well. Finally, we corroborate our findings with numerical experiments.
