Theoretical Nuclear Structure Physics

0140300 Draayer核理论计划在路易斯安那州州立大学（LSU）在巴吞鲁日的重点是了解原子核的结构;具体来说，我们研究的强相互作用，结合核子（中子和质子）在核中的关键成分。 我们所做的工作既有基础科学，也有应用方面：在基础科学方面，我们探索“核汤”-试图理解强相互作用如何在核介质中表现出来，这种相互作用可以深入到核子本身的结构中。 这一点很重要，因为我们不能声称我们真正理解了一个物体，除非我们能把它拆开并重新组装起来。 例如，我们知道，原子核显示出某些特征，如在封闭壳层附近的独立粒子行为和远离封闭壳层的集体旋转（如量子顶的旋转）。 复合系统从复杂的核子-核子相互作用中过滤出来的这些简单特征的驱动因素仍然难以捉摸，因此成为深入理解原子核结构的障碍。 在补充应用科学方面，人们可以通过提出一个非常普遍但重要的问题来更好地理解我们所做的事情的实际含义：“了解负责宇宙中储存的大部分能量的系统和相关过程重要吗？“如果在更深层次上理解这一“终极能源”是重要的，那么核物理学的研究以及培养将指导这一领域未来发展的学生对我们的国家和人类具有真实的价值。 我们正是在这个更大的框架内看待和开展我们的工作。我们对稀土和锕系元素核的结构特别感兴趣，因为在这些核中，集体模通过参与组成核子总数的大部分而得到强烈增强。 这些研究需要超出通常的外壳和集体模型的理论工具，尽管如此，由于其成功，为所有新方法提供了指导和限制。 我们的研究利用对称方法，从点群到q变形和无限维代数，以及非线性动力学。 建议的工作，这将继续我们正在进行的计划，分为三个领域：1）壳模型和相关的调查; 2）群论和代数方法;和3）集体运动和非线性动力学。 最近在这些领域取得的成功分别包括：1）在强变形核中将“扭曲”和“剪刀+扭曲”模式作为集体M1跃迁的接合; 2）广义配对问题的代数解，包括非简并单粒子能量; 3）核中变形演化为液滴表面上的孤子（称为Rotons）。 研究生的培训，大部分来自国外，一直并将继续是我们计划的重要补充教育和外展功能。 到目前为止，在理论核物理程序博士生档案在路易斯安那州立大学是：1非洲裔美国人（第一个在物理从路易斯安那州立大学毕业），1韩国，1巴基斯坦，4德国，1印度尼西亚，1乌克兰，1罗马尼亚，4保加利亚和2亚美尼亚。

0140300DraayerThe nuclear theory program at Louisiana State University (LSU) in Baton Rouge is focused on understanding the structure of atomic nuclei; specifically, we examine key ingredients of the strong interaction that binds nucleons (neutron and protons) in the nucleus. There is both a basic science and an applied aspect to what we do: On the basic science side we probe the "nuclear soup" - trying to understand how the strong interaction, which can be drilled down to a consideration of the structure of the nucleons themselves, manifests itself in the nuclear medium. This is important since we cannot claim we really understand an object unless we can tear it apart and put it back together again. We know, for example, that nuclear display certain characteristic features, such as independent particle behavior near closed shells and collective rotations - like that of a quantum top - away from closed shells. The drivers of these simple characteristics, which the composite system filters from the complex nucleon-nucleon interaction, remain elusive and hence a roadblock to a deeper understanding of the structure of atomic nuclei. On the complementary applied science side, one can gain a better appreciation for practical implications of what we do by asking a very general but important question: "Is it important to understand systems and related processes that are responsible for most of the energy stored in the universe?" If it is important to understand at a deeper level this "ultimate source of energy", then the study of nuclear physics, as well as the training of students who will shepherd future developments in this area, has real value to our nation and humankind. It is within this larger framework that we see and do our work. We are particularly interested in the structure of rare earth and actinide nuclei because in these nuclei that the collective modes are strongly enhanced through the involvement of a large fraction of the total number of constituent nucleons. Such studies require theoretical tools beyond those of the usual shell and collective models, which nonetheless by virtue of their successes provide guidance and limits on all new approaches. Our research exploits symmetry methods, from point groups to q-deformed and infinite-dimensional algebras, as well as non-linear dynamics. The proposed work, which will continue our ongoing program, is organized into three areas: 1) shell-model and related investigations; 2) group theory and algebraic methods; and 3) collective motion and nonlinear dynamics. Recent successes in each of these areas include, respectively: 1) the articulation of "twist" and "scissors + twist" modes as collective M1 transitions in strongly deformed nuclei; 2) an algebraic solution of the generalized pairing problem, inclusive of non-degenerate single-particle energies; and 3) the evolution of deformation in nuclei to solitons (dubbed rotons) on the surface of a liquid drop. The training of graduate students, most from abroad, has been and will continue to be an important complementary educational and out-reach feature of our program. To date, the PhD student profile in theoretical nuclear physics program at LSU is: 1 African- American (the first in physics to graduate from LSU), 1 Korean, 1 Pakistani, 4 Germans, 1 Indonesian, 1 Ukrainian, 1 Romanian, 4 Bulgarian, and 2 Armenian.