Session 1WAB: Computational Nuclear Structure II

Nuclear density functional theory for collective excitation

The finite-amplitude method provides efficient solutions for the collective excitation within the nuclear density functional theory. It has been originally developed for the response functions of giant resonances, and the method recently covers low-energy collective levels, zero-energy Nambu-Goldstone modes, and sum rules, and variety of applications is open. I will overview these recent developments of the framework, and discuss physics of collective inertia for pairing rotation and shape coexistence, and efforts towards determination of next-generation nuclear energy density functional.   

Role of fission in the r-process nucleosynthesis

The rapid neutron capture process (or r process) is responsible for the production of half of the elements heavier than iron that we observe in the Universe. The quest to identify its actual astrophysical site is still ongoing, but there are strong indications including the recent observation of the GW170817 electromagnetic counterpart that make neutron star mergers (NSM) a likely candidate. Reliable estimates of nucleosynthesis yields on NSM require an accurate description of the relevant nuclear physics inputs, including fission properties of heavy and superheavy nuclei. In this talk I will present a recent calculation of the fission properties of nuclei in the range 84 ≤ Z ≤ 120 and 120 ≤ N ≤ 250 calculated using the nuclear energy density functional approach (EDF). A new set of spontaneous, neutron-induced and beta-delayed fission rates are obtained from a microscopic calculation of the fission barriers and collective inertias. These fission rates are used as a nuclear input in r-process nucleosynthesis calculations in NSM. I will also present recent developments in the estimation of fission yields of superheavy nuclei and the possible extension to the r-process region. This constitutes a first step in a systematic exploration of different sets of fission rates and yields on r-process abundance predictions.   

Nuclear Superfluid Dynamics within TDSLDA

In spite of the known great importance of the pairing in nuclear structure studies, the effect of pairing on nuclear dynamics has rarely been investigated to date. We attack this problem by applying a microscopic dynamic approach, Time-Dependent Density Functional Theory (TDDFT) extended for superfluid systems with local treatment of pairing, known as Time-Dependent Superfluid Local Density Approximation (TDSLDA) (see, e.g., [1]). Its application started only very recently with top-tier supercomputers. In this talk, I will first digest the theoretical framework of TDSLDA and its applications to a variety of nuclear dynamics: giant resonances [2,3], fission [4,5], heavy-ion reactions [6], and superfluid vortices in the inner crust of neutron stars [7]. Especially, I will put special focus on dynamics of quantized vortices in the presence of nuclear impurities [7], which govern vortex pinning mechanism at the heart of the pulsar glitch phenomenon, a sudden change of the rotational frequency of a neutron star (see, e.g., [8]).