发表机构
Karlsruhe Institute of Technology; Technical University of Applied Science Regensburg; Siemens AG, Foundational Technology（卡尔斯鲁厄理工学院; 雷根斯堡应用技术大学; 西门子股份公司基础技术）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
JAQSI是一个基于JAX的可微量子模拟器，结合门级与脉冲级模拟，通过门融合和伴随微分加速，在基准测试中性能优于或媲美主流模拟器，并开源发布。
AI 中文摘要
经典模拟通过全态检查、受控噪声模型和反向传播支持量子算法的开发和验证，尽管仅限于小型量子系统。现有框架提供门级执行、可微脉冲级动力学或优化的硬件执行。JAQSI（Just Another Quantum Simulator）在基于JAX的可微电路模型中结合了门级和脉冲级模拟。电路表示为数值输入的纯函数，支持向量化批处理和JIT编译。在单个电路内，矩阵定义的操作、由哈密顿量时间演化合成的门以及噪声通道可以自由组合。为了快速模拟，门和通道融合减少了状态上的遍历次数，而伴随微分以恒定数量的态矢量计算期望值梯度。在脉冲级，JAQSI将单项哈密顿量下的演化简化为标量脉冲面积积分，并重用缓存的执行计划和编译的求解器。在基准测试中，我们将JAQSI与PennyLane、Qiskit、Qibo、Qulacs、QuTiP和dynamiqs进行比较。在门级，我们观察到在态矢量、密度、噪声和梯度模拟方面，性能与所比较的模拟器相当或快一个数量级，最高可达12个量子比特。超过18个量子比特时，JAQSI在态矢量和梯度模拟方面与PennyLane Lightning相当。在态矢量和含噪密度矩阵脉冲基准测试中，即使禁用其闭式求解，它也比其他模拟器快至少5倍。禁用后者使其运行时间最多增加1.5倍。我们将JAQSI作为开源软件在GitHub和PyPI上提供。
英文摘要
Classical simulation supports the development and validation of quantum algorithms through full-state inspection, controlled noise models and backpropagation, albeit for small quantum systems. Existing frameworks offer gate-level execution, differentiable pulse-level dynamics or optimised hardware execution. Just another quantum simulator (JAQSI) combines gate- and pulse-level simulation in one differentiable circuit model built upon JAX. Circuits are represented as pure functions of numerical inputs which support vectorised batches and JIT compilation. Within a single circuit, matrix-defined operations, gates synthesised from Hamiltonian time evolution and noise channels can be composed freely. For a fast simulation, gate and channel fusion reduces passes over the state, while adjoint differentiation computes expectation-value gradients with a constant number of statevectors. At pulse level, JAQSI reduces evolution under single-term Hamiltonians to a scalar pulse-area integral and reuses cached execution plans and compiled solvers. In a benchmark we compare JAQSI with PennyLane, Qiskit, Qibo, Qulacs, QuTiP and dynamiqs. At gate level, we observe performance either on par or an order of magnitude faster across statevector, density, noise and gradient simulation than the compared simulators up to 12 qubits. Beyond 18 qubits, JAQSI is on par with PennyLane Lightning in both statevector and gradient simulation. In the statevector and noisy density-matrix pulse benchmarks, it is at least 5 times faster than the other simulators, even with its closed-form solve disabled. Disabling the latter increases its runtime by at most a factor of 1.5. We provide JAQSI as open-source software on GitHub and PyPI.
