标题： 通过中电路测量和动态电路从单个副本捕获量子快照 显示英文标题

标题： Capturing Quantum Snapshots from a Single Copy via Mid-Circuit Measurement and Dynamic Circuit

摘要： 我们提出量子快照动态电路（QSDC），这是一种与硬件无关的、学习驱动的框架，用于捕捉量子快照：在量子电路中的任意点对量子态进行非破坏性估计，这些估计可以被经典存储并在之后重建。 这种功能对于量子系统的内部观察、调试和记忆至关重要，但仍然受到不可克隆定理和测量的破坏性本质的根本限制。 QSDC引入了一种猜测和检查的方法，其中由基于梯度的神经网络或无梯度的进化策略驱动的经典模型被训练，使用SWAP测试的保真度作为唯一的反馈信号来重建未知的量子态。 我们的方法支持单拷贝、中电路状态重建，假设硬件具备动态电路支持和足够的相干时间。 我们在模拟和IBM量子硬件上验证了QSDC的核心组件。 在无噪声的情况下，我们的模型在100个随机量子态上的平均保真度达到0.999；在真实设备上，我们能够在三个优化步骤内准确重建已知的单量子比特状态（例如，Hadamard）。 显示英文摘要

摘要： We propose Quantum Snapshot with Dynamic Circuit (QSDC), a hardware-agnostic, learning-driven framework for capturing quantum snapshots: non-destructive estimates of quantum states at arbitrary points within a quantum circuit, which can then be classically stored and later reconstructed. This functionality is vital for introspection, debugging, and memory in quantum systems, yet remains fundamentally constrained by the no-cloning theorem and the destructive nature of measurement. QSDC introduces a guess-and-check methodology in which a classical model, powered by either gradient-based neural networks or gradient-free evolutionary strategie, is trained to reconstruct an unknown quantum state using fidelity from the SWAP test as the sole feedback signal. Our approach supports single-copy, mid-circuit state reconstruction, assuming hardware with dynamic circuit support and sufficient coherence time. We validate core components of QSDC both in simulation and on IBM quantum hardware. In noiseless settings, our models achieve average fidelity up to 0.999 across 100 random quantum states; on real devices, we accurately reconstruct known single-qubit states (e.g., Hadamard) within three optimization steps.