论文标题
自发裂变中集体惯性的有限振幅法
Finite-amplitude method for collective inertia in spontaneous fission
论文作者
论文摘要
背景：自发裂变的微观描述是核物理学中最具挑战性的主题之一。有必要评估沿裂变路径沿裂变路径的集体潜力和集体惯性，以描述自发或低能裂变中的量子隧穿。在基于核能密度功能（EDF）理论的裂变动力学的过去研究中，已经通过曲柄近似评估了集体惯性，从而忽略了动态残留效应。目的：目的是提供一种可靠，有效的方法，以在集体惯性中包含动态残留效应以进行裂变动力学。方法：我们使用局部准粒子随机相近似（LQRPA）来评估沿着Skyrme EDF的约束Hartree-fock-Bogoliubov方法获得的裂变路径的集体惯性。具有轮廓集成技术的有限振幅方法（FAM）使我们能够在大型模型空间中有效计算集体惯性。结果：我们沿着$^{240} $ pu和$^{256} $ fm的对称裂变路径评估FAM-QRPA集体惯性。 FAM-QRPA惯性明显大于曲柄近似之一，并显示在基态和裂变异构体周围的明显峰。这是由于动态残留效应。结论：为了描述自发性或低能裂变，我们提供了一种可靠，有效的方法来构建具有动态残留效应的集体惯性，这些惯性在过去的大多数基于EDF的作品中都被忽略了。我们表明了动态残留效应对集体惯性的重要性。这项工作将是对沉重和超重核中裂变动力学进行系统研究的起点，以微观描述核大振幅集体运动。
Background: Microscopic description of spontaneous fission is one of the most challenging subjects in nuclear physics. It is necessary to evaluate the collective potential and the collective inertia along a fission path for a description of quantum tunneling in spontaneous or low-energy fission. In past studies of the fission dynamics based on nuclear energy density functional (EDF) theory, the collective inertia has been evaluated with the cranking approximation, which neglects dynamical residual effects. Purpose: The purpose is to provide a reliable and efficient method to include dynamical residual effects in the collective inertia for fission dynamics. Methods: We use the local quasiparticle random-phase approximation (LQRPA) to evaluate the collective inertia along a fission path obtained by the constrained Hartree-Fock-Bogoliubov method with the Skyrme EDF. The finite-amplitude method (FAM) with a contour integration technique enables us to efficiently compute the collective inertia in a large model space. Results: We evaluate the FAM-QRPA collective inertia along a symmetric fission path in $^{240}$Pu and $^{256}$Fm. The FAM-QRPA inertia is significantly larger than the one of the cranking approximation, and shows pronounced peaks around the ground state and the fission isomer. This is due to dynamical residual effects. Conclusions: To describe the spontaneous or low-energy fission, we provide a reliable and efficient method to construct the collective inertia with dynamical residual effects that have been neglected in most of EDF-based works in the past. We show the importance of dynamical residual effects to the collective inertia. This work will be a starting point for a systematic study of fission dynamics in heavy and superheavy nuclei to microscopically describe the nuclear large-amplitude collective motions.
