Otsuka T, Abe T, Yoshida T, Tsunoda Y, Shimizu N, Itagaki N, Utsuno Y, Vary J, Maris P, Ueno H
Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan.
RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
Nat Commun. 2022 Apr 27;13(1):2234. doi: 10.1038/s41467-022-29582-0.
A long-standing crucial question with atomic nuclei is whether or not α clustering occurs there. An α particle (helium-4 nucleus) comprises two protons and two neutrons, and may be the building block of some nuclei. This is a very beautiful and fascinating idea, and is indeed plausible because the α particle is particularly stable with a large binding energy. However, direct experimental evidence has never been provided. Here, we show whether and how α(-like) objects emerge in atomic nuclei, by means of state-of-the-art quantum many-body simulations formulated from first principles, utilizing supercomputers including K/Fugaku. The obtained physical quantities exhibit agreement with experimental data. The appearance and variation of the α clustering are shown by utilizing density profiles for the nuclei beryllium-8, -10 and carbon-12. With additional insight by statistical learning, an unexpected crossover picture is presented for the Hoyle state, a critical gateway to the birth of life.
原子核长期以来的一个关键问题是那里是否发生α团簇现象。α粒子（氦-4原子核）由两个质子和两个中子组成，可能是一些原子核的组成单元。这是一个非常美妙且引人入胜的想法，而且确实有其合理性，因为α粒子具有特别大的结合能，因而特别稳定。然而，从未有过直接的实验证据。在此，我们借助基于第一性原理构建的、利用包括K/Fugaku在内的超级计算机进行的最先进的量子多体模拟，展示了α（类）物体在原子核中是否出现以及如何出现。所获得的物理量与实验数据相符。通过利用铍-8、-10和碳-12原子核的密度分布，展示了α团簇的出现和变化。通过统计学习的进一步深入分析，呈现了关于霍伊尔态（生命诞生的关键通道）的一幅意想不到的交叉图景。
