论文标题
降低相似性转化的电子哈密顿量在Qubit空间中
Growth reduction of similarity transformed electronic Hamiltonians in qubit space
论文作者
论文摘要
通过当前和近期设备的可用量子资源阻碍,通过变异量子本质量(VQE)准确地解决电子结构问题。缓解VQE电路深度要求的一种方法是通过结合某种程度的电子相关性的相似性转换来“预处理”电子哈密顿量的“预处理”,其余的相关性则由电路ANSATZ解决。这通常是以衡量相似性转变为哈密顿量的术语数量大幅增加的代价。在这项工作中,我们提出了一种有效的方法来对完整的Pauli Group采样元素,以$ n $ Qubits的价格最大程度地减少了转型的Hamiltonian中新术语的发作,同时促进了实质性的降低能量。我们基于适用于H $ _4 $,n $ _2 $和H $ _2 $ o分子系统的模型的基础状态能量估计的生长降低发电机选择技术。已经发现,利用一种从具有最大能量梯度的运算符中获得生长最小化的发电机的选择程序是减少汉密尔顿术语开始的最大竞争方法,同时降低参考状态的系统能量。
Accurately solving the electronic structure problem through the variational quantum eigensolver (VQE) is hindered by the available quantum resources of current and near-term devices. One approach to relieving the circuit depth requirements for VQE is to "pre-process" the electronic Hamiltonian by a similarity transformation incorporating some degree of electronic correlation, with the remaining correlation left to be addressed by the circuit ansatz. This often comes at the price of a substantial increase in the number of terms to measure in the similarity transformed Hamiltonian. In this work, we propose an efficient approach to sampling elements from the complete Pauli group for $N$ qubits which minimize the onset of new terms in the transformed Hamiltonian, while facilitating substantial energy lowering. We benchmark the growth-mitigating generator selection technique for ground state energy estimations applied to models of the H$_4$, N$_2$ and H$_2$O molecular systems. It is found that utilizing a selection procedure which obtains the growth-minimizing generator from the set of operators with maximal energy gradient is the most competitive approach to reducing the onset of Hamiltonian terms while achieving systematic energy lowering of the reference state.