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arXiv 2103.14480nucl-th
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基于从头计算的核能密度泛函

Nuclear energy density functionals grounded in ab initio calculations

F. Marino, C. Barbieri, G. Colò, A. Lovato, F. Pederiva, X. Roca-Maza, E. Vigezzi

摘要:

我们讨论了从头计算的核能密度泛函(EDF)的建设,我们主张需要一个有条不紊的方法,是免费的特设假设。分别采用手征非线性非线性$_{\rm sat}$和唯象AV4 $^\prime$ +UIX $_{c}$哈密顿量作为自洽格林函数(SCGF)和辅助场扩散蒙特卡罗(AFDMC)方法的输入,计算了对称核物质和纯中子物质的物态方程.我们提出了一个方便的参数化的EoS作为费米动量的函数,并适合它的SCGF和AFDMC计算。在局域密度近似下,我们应用从头算EDF方法对不同核的结合能和电荷半径进行了分析。基于NNLO $_{\rm sat}$的EDF产生了令人鼓舞的结果,而基于AV4 $^\prime$ +UIX $_{c}$的EDF离实验更远。这些不同的行为可能的解释建议,并分析了梯度和自旋轨道项的重要性。我们的工作铺平了道路,一个实用的和系统的方法来合并从头算核理论和DFT,而在同一时间,它揭示了这个过程的一些关键方面。

英文摘要:

We discuss the construction of a nuclear Energy Density Functional (EDF) from ab initio calculations, and we advocate the need of a methodical approach that is free from ad hoc assumptions. The equations of state (EoS) of symmetric nuclear and pure neutron matter are computed using the chiral NNLO$_{\rm sat}$ and the phenomenological AV4$^\prime$+UIX$_{c}$ Hamiltonians as inputs in the Self-consistent Green's Function (SCGF) and Auxiliary Field Diffusion Monte Carlo (AFDMC) methods, respectively. We propose a convenient parametrization of the EoS as a function of the Fermi momentum and fit it on the SCGF and AFDMC calculations. We apply the ab initio-based EDF to carry out an analysis of the binding energies and charge radii of different nuclei in the local density approximation. The NNLO$_{\rm sat}$-based EDF produces encouraging results, whereas the AV4$^\prime$+UIX$_{c}$-based one is farther from experiment. Possible explanations of these different behaviors are suggested, and the importance of gradient and spin-orbit terms is analyzed. Our work paves the way for a practical and systematic way to merge ab initio nuclear theory and DFT, while at the same time it sheds light on some of the critical aspects of this procedure.

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