从头算核结构计算中理论不确定性的平衡：多体截断与有限基矢尺寸
Balancing theory uncertainties in ab initio nuclear structure calculations: Many-body truncation versus finite basis size
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中文总结 AI 辅助
该研究针对从头算核结构计算的不确定性，提出平衡多体截断与有限基矢尺寸的最优单粒子基矢判据，通过多体微扰理论等验证，发现采用依赖多体阶数的基矢可节省计算资源。
中文摘要 AI 辅助
原子核的第一性原理计算必然存在不完整性，因为求解薛定谔方程时采用了近似方法，且所用希尔伯特空间的维度有限。通过平衡多体截断和基矢尺寸的不确定性，我们为给定从头算核结构计算中的最优单粒子基矢维度制定了一个判据。接着，研究表明，当目标计算精度一致时，高阶多体贡献可采用比低阶更小的基矢尺寸进行计算。我们采用多体微扰理论和耦合簇方法，结合两组手征两核子与三核子相互作用，对核素图中大部分核素进行计算，以此对上述发现进行经验验证。结果显示，采用依赖多体阶数的单粒子基矢尺寸可显著节省计算资源。
英文摘要
First-principles calculations of atomic nuclei are necessarily incomplete as the Schrödinger equation is solved using approximate methods and due to the finite dimension of the employed Hilbert space. By balancing many-body truncation and basis-size uncertainties, we formalize a criterion for the optimal one-body basis dimension in a given ab initio nuclear structure computation. Next, it is demonstrated that higher-order many-body contributions can be computed using smaller basis sizes than used for the lower orders when a consistent accuracy in the calculation is targeted. Our findings are empirically validated using many-body perturbation theory and coupled-cluster calculations of nuclei spanning a large portion of the nuclear chart using two sets of chiral two- and three-nucleon interactions. The results suggest that considerable computational savings can be obtained using many-body-order-dependent one-body basis sizes.
