Nonstoquastic Hamiltonians are hard to simulate due to the sign problem in quantum Monte Carlo simulation. It is, however, unclear whether nonstoquasticity can lead to advantage in quantum annealing. Here we show that $YY$ interactions between the qubits make the adiabatic path during quantum annealing, and therefore the performance, dependent on spin-reversal transformations. With the right choice of spin-reversal transformation, a nonstoquastic Hamiltonian with $YY$ interaction can outperform stoquastic Hamiltonians with similar parameters. We introduce an optimization protocol to determine the optimal transformation and discuss the effect of suboptimality.

中文翻译：

---

用自旋反转变换改进非随机量子退火

由于量子蒙特卡罗模拟中的符号问题，非随机哈密顿量很难模拟。然而，目前尚不清楚非随机性是否会导致量子退火的优势。这里我们证明$是是$量子位之间的相互作用在量子退火过程中形成绝热路径，因此性能取决于自旋反转变换。随着自旋反转变换的正确选择，具有$是是$相互作用可以胜过具有相似参数的随机哈密顿量。我们引入了一个优化协议来确定最优转换并讨论次优的影响。