论文标题
通过用猪棍门进行几乎理想的采样来评估热期望值
Evaluating thermal expectation values by almost ideal sampling with Trotter gates
论文作者
论文摘要
我们研究了通过将trottter门应用于随机相产品状态（RPPSS）来生成的，研究有限温度下量子多体系统模拟的采样效率。我们限制了猪门的应用数量与系统大小成比例，因此可以轻松地在容忍失误的量子计算机中完成准备。当猪门是由不可整合的哈密顿量制成的时，我们观察到采样效率随系统尺寸的增加而增加。这种趋势意味着在足够大的系统中可以实现几乎理想的初始状态采样。我们还发现，采样效率几乎等于在某些情况下利用HAAR随机采样的典型纯量子（TPQ）方法获得的采样效率。这些发现表明，混乱的汉密尔顿动力学可以将RPPS转变为TPQ状态的替代方案，以评估热期望值。
We investigate the sampling efficiency for the simulations of quantum many-body systems at finite temperatures when initial sampling states are generated by applying Trotter gates to random phase product states (RPPSs). We restrict the number of applications of Trotter gates to be proportional to the system size, and thus the preparation would be easily accomplished in fault-tolerant quantum computers. When the Trotter gates are made from a nonintegrable Hamiltonian, we observe that the sampling efficiency increases with system size. This trend means that almost ideal sampling of initial states can be achieved in sufficiently large systems. We also find that the sampling efficiency is almost equal to that obtained by a typical pure quantum (TPQ) state method utilizing Haar random sampling in some cases. These findings suggest that chaotic Hamiltonian dynamics can transform RPPSs into an alternative to TPQ states for evaluating thermal expectation values.
