The unitary coupled cluster (UCC) ansatz is a promising tool for achieving high-precision results using the variational quantum eigensolver (VQE) algorithm in the NISQ era. However, results on quantum hardware are thus far very limited and simulations have only accessed small system sizes. We advance the state of the art of UCC simulations by utilizing an efficient sparse wavefunction circuit solver and studying systems up to 64 qubits. Here we report results obtained using this solver that demonstrate the power of the UCC ansatz and address pressing questions about optimal initial parameterizations and circuit construction, among others. Our approach enables meaningful benchmarking of the UCC ansatz, a crucial step in assessing the utility of VQE for achieving quantum advantage.

中文翻译：

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超越酉耦合簇量子电路的 MP2 初始化


在 NISQ 时代，幺正耦合簇 （UCC） 拟设是一种很有前途的工具，用于使用变分量子特征求解器 （VQE） 算法获得高精度结果。然而，到目前为止，量子硬件上的结果非常有限，模拟只访问了较小的系统规模。我们利用高效的稀疏波函数电路求解器并研究多达 64 个量子比特的系统，从而推进了 UCC 仿真的最新技术。在这里，我们报告了使用此求解器获得的结果，这些结果展示了 UCC ansatz 的强大功能，并解决了有关最佳初始参数化和电路构建等的紧迫问题。我们的方法能够对 UCC ansatz 进行有意义的基准测试，这是评估 VQE 实现量子优势的效用的关键一步。