论文标题
通过有效的哈密顿理论减少自适应变分量子算法的回路深度
Reducing circuit depth in adaptive variational quantum algorithms via effective Hamiltonian theories
论文作者
论文摘要
电子结构模拟是量子计算机的预期应用。由于在密切相关的系统中的高维量子纠缠，进行此类模拟所需的量子资源远远超出了当前量子设备的能力。为了降低量子电路的复杂性，已建议将电子相关性的一部分结合到有效的哈密顿量中，这通常是从电子汉密尔顿的相似性转化中获得的。在这项工作中，我们以激发操作员的线性组合形式引入了一种新的转换，以用有限的术语构建有效的哈密顿量。为了证明其准确性，我们还考虑了具有这种转换的等效自适应变分算法，并表明它可以获得准确的基态波函数。通过这种新转换定义的有效汉密尔顿人被纳入自适应变化量子算法中，以维持恒定尺寸的量子电路。通过对小分子进行数值模拟来评估新的计算方案。化学精度是通过较浅的电路深度实现的。
Electronic structure simulation is an anticipated application for quantum computers. Due to high-dimensional quantum entanglement in strongly correlated systems, the quantum resources required to perform such simulations are far beyond the capacity of current quantum devices. To reduce the quantum circuit complexity, it has been suggested to incorporate a part of the electronic correlation into an effective Hamiltonian, which is often obtained from a similarity transformation of the electronic Hamiltonian. In this work, we introduce a new transformation in the form of a product of a linear combination of excitation operators to construct the effective Hamiltonian with finite terms. To demonstrate its accuracy, we also consider an equivalent adaptive variational algorithm with this transformation and show that it can obtain an accurate ground state wave function. The effective Hamiltonian defined with this new transformation is incorporated into the adaptive variational quantum algorithms to maintain constant-size quantum circuits. The new computational scheme is assessed by performing numerical simulations for small molecules. Chemical accuracy is achieved with a much shallower circuit depth.
