用于分子模拟的改进量子采样方法
Improved quantum sampling methods for molecular simulations
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中文总结 AI 辅助
本研究针对分子模拟的量子采样方法，发现SQD性能受经典对角化子空间增长影响，提出基于NOCI的测量协议，确立测量基工程是改进量子采样方法的有前景途径。
中文摘要 AI 辅助
量子选择组态相互作用（QSCI）方法利用量子计算机识别分子基态中的主导电子组态，同时由经典计算机在这些组态张成的约化子空间内对角化哈密顿量。基于采样的量子对角化（SQD）是QSCI的主流方法，它通过迭代经典后处理校正有噪声的量子测量，以确保对应组态保持物理合理性。本研究表明，SQD的性能会受到经典对角化子空间不受控增长的强烈影响：当未明确约束经典资源时，随着噪声增加采样组态的多样性，经典均匀随机采样可复现SQD的基准结果。我们证明，任何公平的SQD基准测试协议都必须明确控制唯一采样的对角化规模。随后，我们通过引入基于非正交组态相互作用（NOCI）的测量协议，解决高效发现与物理相关且可降低能量的组态的问题。通过在针对分子哈密顿量优化的轨道基上分配测量，我们获得了相对于仅在Hartree–Fock基上执行测量的改进采样效率。重要的是，这些改进在固定经典资源预算下仍能保持，表明所得组态质量更高而非数量更多。在我们提出的基准测试流程下，我们确立测量基工程是改进电子结构量子采样方法的有前景途径。
英文摘要
Quantum-selected configuration interaction (QSCI) methods use a quantum computer to identify dominant electronic configurations in the molecular ground state, while a classical computer diagonalizes the Hamiltonian within the reduced subspace spanned by those configurations. Sample-based quantum diagonalization (SQD), a leading QSCI approach, uses iterative classical post-processing to correct noisy quantum measurement to ensure that the corresponding configurations remain physically sensible. In this work, we show that SQD performance can be strongly influenced by uncontrolled growth of the classical diagonalization subspace. When classical resources are not explicitly constrained, classical uniform random sampling can reproduce SQD benchmarks as noise increases the diversity of sampled configurations. We show any fair benchmarking protocol of SQD must explicitly control diagonalization size over unique samples. We then address the problem of efficiently discovering physically relevant, energy-lowering configurations by introducing a measurement protocol based on non-orthogonal configuration interaction (NOCI). By distributing measurements across orbital bases optimized with respect to the molecular Hamiltonian, we obtain improved sample efficiency relative to measurements performed solely in the Hartree--Fock basis. Importantly, these improvements persist even under fixed classical resource budgets, demonstrating that the resulting configurations are of higher quality rather than being more numerous. Under our proposed benchmarking procedure, we establish measurement-basis engineering as a promising route to improving quantum sampling methods for electronic structure.
发表机构
- University of Queensland（昆士兰大学）
- The MITRE Corporation（MITRE公司）
机构由 AI 辅助整理，请以论文原文为准。
