标题： 捕捉CaCuO$_2$中的自旋涨落：使用多决定子波函数的$\textit{Ab initio}$QMC计算 显示英文标题

标题： Capturing spin fluctuations in CaCuO$_2$: $\textit{Ab initio}$ QMC calculations with multi-determinant wave functions

摘要： 我们提出了一种先进的$\textit{ab initio}$量子蒙特卡罗 (QMC) 计算，用于计算未掺杂的 CaCuO$_2$的基态。 我们将传统的单行列式 Slater-Jastrow 方法扩展为包括多行列式波函数、非均匀 Jastrow 因子和轨道优化。 我们的结果不仅显示了基态能量的变分上限的改进——每公式单位比之前最先进的技术低 2.3 eV——还证实了在强关联铜氧化物系统中多行列式波函数中的自旋涨落的存在，这对于理解高温$T_c$超导性至关重要。 这是首次在铜氧化物中通过 QMC 波函数捕捉到自旋涨落，为在超导态下对掺杂铜氧化物的新研究奠定了基础，其中自旋涨落需要更精确的表征。 显示英文摘要

摘要： We present an advanced $\textit{ab initio}$ quantum Monte Carlo (QMC) calculation of the ground state of undoped CaCuO$_2$. We extend the traditional single-determinant Slater-Jastrow approach to include multi-determinant wave functions, inhomogeneous Jastrow factors, and orbital optimization. Our results demonstrate not only an improvement in the variational bound of the ground state energy -- 2.3 eV per formula unit lower than previous state of the art techniques -- but also confirm the presence of spin fluctuations in multi-determinant wave functions in a strongly correlated cuprate system, which is integral to understanding high-$T_c$ superconductivity. This is the first demonstration of capturing spin fluctuations in QMC wave functions on a cuprate, establishing the groundwork for new studies on doped cuprates in the superconducting state, where spin fluctuations require more accurate characterization.