论文标题
比较量子和经典横向场退火中的松弛机制
Comparing relaxation mechanisms in quantum and classical transverse-field annealing
论文作者
论文摘要
退火计划控制提供了新的机会，以更好地了解推定的量子退火器运作的方式和机制。通过适当地修改退火时间表以包括一段时间内的停顿（保持哈密顿量修复），我们表明可以更直接地探测系统在沿着退火的中间点处系统的耗散动态并检查热弛豫率，例如，通过观察最小频谱距离之后的基态重新配置。我们提供了来自D波设备的实验的详细比较，量子绝热主方程的模拟以及量子退火，自旋矢量蒙特卡洛的经典类似物，我们观察到定性一致性，表明在暂停时成功概率的特征增加并不是一种奇妙的量子现象。我们发现系统中的放松是由单个时间尺度主导的，这使我们能够为我们期望暂停改善时间到解决的时间，即经典优化的相关指标。最后，我们还探索了模拟温度的作用，而暂停的作用是更好地区分量子退火器的量子和经典模型。
Annealing schedule control provides new opportunities to better understand the manner and mechanisms by which putative quantum annealers operate. By appropriately modifying the annealing schedule to include a pause (keeping the Hamiltonian fixed) for a period of time, we show it is possible to more directly probe the dissipative dynamics of the system at intermediate points along the anneal and examine thermal relaxation rates, for example, by observing the re-population of the ground state after the minimum spectral gap. We provide a detailed comparison of experiments from a D-Wave device, simulations of the quantum adiabatic master equation and a classical analogue of quantum annealing, spin-vector Monte Carlo, and we observe qualitative agreement, showing that the characteristic increase in success probability when pausing is not a uniquely quantum phenomena. We find that the relaxation in our system is dominated by a single time-scale, which allows us to give a simple condition for when we can expect pausing to improve the time-to-solution, the relevant metric for classical optimization. Finally, we also explore in simulation the role of temperature whilst pausing as a means to better distinguish quantum and classical models of quantum annealers.
