α-Clustering in atomic nuclei from first principles with statistical learning and the Hoyle state character

A long-standing crucial question with atomic nuclei is whether or not alpha clustering occurs there. An alpha 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 alpha particle is particularly stable with a large binding energy. However, direct experimental evidence has never been provided. Here, we show whether and how alpha(-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 alpha 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. Alpha particles are considered the building blocks for some nuclei in alpha-clustering. Here the authors discuss quantum many-body simulations with nucleon-nucleon interaction to characterize the Hoyle state, the first excited 0+ state of the 12C nucleus, and find complexity in its alpha-clustering.

Automated summary

In this study, the authors utilize quantum many-body simulations to investigate the existence and characteristics of alpha clustering in atomic nuclei. Through density profiles and statistical learning, they demonstrate the emergence and variation of alpha-like objects, providing insights into the complexity of alpha clustering in key states.