Microscopic nuclear reaction theory for low-energy fusion and fission

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K03861
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Kyoto University
• Principal Investigator: Hagino Kouichi 京都大学, 理学研究科, 教授 (20335293)
• Co-Investigator(Kenkyū-buntansha): 谷村 雄介 東北大学, 理学研究科, 助教 (90804310)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 生成座標法 / トンネル効果 / 核融合 / 核分裂 / 時間依存アプローチ / 基底状態相関 / 機械学習

Outline of Final Research Achievements

By considering a time evolution of a system based on the time-dependent generator coordinate method (TDGCM) with multi Slater determinants, we could for the first time describe microscopically quantum tunneling of a many-particle system. Namely, even in a situation where the tunneling probability is zero with a single Slater determinant, we obtained a finite tunneling probability by linearly superposing many Slater determinants. We also applied the same method to the ground state of atomic nuclei. By optimizing both the basis Slater determinants and the coefficients for a linear superposition, we showed that a better description for the ground state can be achieved by including not only the local ground states but also excited state configurations. This is in contrast to the usual assumption of GCM, in which only local ground states are superposed, and has a large impact on theory of large amplitude collective motions of atomic nuclei.

Free Research Field

原子核理論

Academic Significance and Societal Importance of the Research Achievements

これまで量子トンネル現象が本質的な役割を果たす低エネルギー領域における核融合反応を微視的に記述する核反応理論はほとんど皆無であったが、本研究により多粒子系の量子トンネル現象を微視的に記述する筋道を見いだせた意義は大きい。また、原子核の基底状態に対する知見は、局所基底状態の重ね合せで系の基底状態を記述できるというこれまで信じられてきた仮定を大きく覆すものであり、原子核の集団運動の理論の発展に大きな影響を及ぼすものである。