We found the same staggering pattern in the evolution of the spin-orbit (SO) and pseudospin-orbit (PSO) splittings in neutron drops obtained by the energy-density functional (EDF) theory using SAMi-T and SLy5 parameterizations, with and without the tensor terms respectively. This staggering evolution is similar to the results recently obtained by the relativistic Brueckner-Hartree-Fock (RBHF) theory with Bonn A potential, which was claimed to be a tensor effect. In this work, we present an intuitive but essential explanation on the origin of this staggering evolution in the Skyrme EDF theory. We found that for both the SO and PSO partners, the energy splittings mainly originate from the SO potential. The staggering evolution of both the SO and PSO splittings is mainly due to the drastic change of density while neutrons filling different single-particle orbits. The key to determine the specific staggering pattern is the strength of the neutron density gradient term and the SO density term in the SO potential, not necessarily the tensor force.

中文翻译：

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中子滴中自旋轨道和伪自旋轨道分裂演化的起源

我们在使用SAMi-T和SLy5参数化通过能量密度泛函（EDF）理论获得的中子液滴中的自旋轨道（SO）和伪自旋轨道（PSO）分裂的演化中发现了相同的错开模式张量项。这种惊人的演变类似于最近通过具有波恩A势的相对论性Brueckner-Hartree-Fock（RBHF）理论获得的结果，据称这是张量效应。在这项工作中，我们对Skyrme EDF理论中这种惊人发展的起源提出了直观但必不可少的解释。我们发现，对于SO和PSO合作伙伴而言，能源分裂主要来自SO潜力。SO和PSO分裂的惊人演变主要是由于中子填充了不同的单粒子轨道时密度的急剧变化。确定特定交错模式的关键是SO势中的中子密度梯度项和SO密度项的强度，不一定是张量。