发表机构
Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China; Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China; Hefei National Laboratory, University of Science and Technology of China; Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University; Center on Frontiers of Computing Studies, School of Computer Science, Peking University（合肥微尺度物质科学国家研究中心和中国科学技术大学物理学院; 上海量子科学研究中心和中国科学院量子信息重点实验室（中国科学技术大学）; 合肥国家实验室（中国科学技术大学）; 教育部理论化学与计算化学重点实验室和北京师范大学化学学院; 前沿计算研究中心和北京大学生命科学学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对量子化学动力学模拟，提出非正交变分量子模拟（NOVQS），通过线性组合浅层参数化量子电路增强表达能力，在电路深度受限下提升模拟精度。
AI 中文摘要
量子多体系统的动力学模拟是量子化学中的核心任务，需要高效的波函数表示。尽管张量网络和神经网络量子态在基态计算中取得了显著成功，但纠缠增长阻碍了它们在量子动力学中的应用。量子计算可能提供实现量子优势的途径，但诸如Trotter化之类的算法通常需要容错量子计算机，而近期的硬件仅支持有限的电路规模。变分量子模拟（VQS）则用单个浅层、固定大小的参数化量子电路（PQC）来表示演化状态。在此，我们引入了非正交变分量子模拟（NOVQS），它将参数化量子态的线性组合应用于实时间和虚时间演化。我们设计了一个浅层、硬件友好的拟设，专门针对第二量子化的电子结构哈密顿量，并提供了用于测量参数运动方程中矩阵和向量的资源高效协议。我们还提供了误差分析和资源估算。对氢链和氮分子的数值模拟表明，一组浅层甚至单层的PQC在VQS中可以匹配或超越更深的PQC。特别是，我们发现了电路数量与深度之间的权衡。因此，NOVQS提供了一种在电路深度约束下增强波函数表达能力的灵活途径，使其成为在近期量子处理器上进行量子动力学模拟的有前景的框架。
英文摘要
Dynamical simulation of quantum many-body systems is a central task in quantum chemistry and requires efficient wavefunction representations. Although tensor-network and neural-network quantum states have achieved considerable success in ground-state calculations, entanglement growth hinders their application to quantum dynamics. Quantum computing may offer a route to quantum advantage, but algorithms such as Trotterization generally require fault-tolerant quantum computers, whereas near-term hardware supports only limited circuit sizes. Variational quantum simulation (VQS) instead represents the evolving state with a single shallow, fixed-size parameterized quantum circuit (PQC). Here, we introduce nonorthogonal variational quantum simulation (NOVQS), which applies linear combinations of parameterized quantum states to real- and imaginary-time evolutions. We design a shallow, hardware-friendly ansatz tailored to second-quantized electronic-structure Hamiltonians, together with resource-efficient protocols for measuring the matrices and vectors in the parameter equations of motion. Error analysis and resource estimation are also provided. Numerical simulations of hydrogen chains and the nitrogen molecule demonstrate that a collection of shallow, or even single-layer, PQCs can match or outperform a much deeper PQC in VQS. In particular, we identify a trade-off between circuit number and depth. NOVQS therefore provides a flexible route to enhancing wavefunction expressivity under circuit-depth constraints, making it a promising framework for quantum dynamics simulations on near-term quantum processors.
Comments19 pages, 12 figures
