Nuclear collective dynamics in transport model with the lattice Hamiltonian method

TL;DR

This paper reviews a lattice Hamiltonian method for studying nuclear collective dynamics via the BUU equation, highlighting its development, GPU implementation, and application to giant resonances, revealing the importance of NN scattering.

Contribution

The paper introduces the lattice BUU method with GPU acceleration for accurate nuclear dynamics simulation, including collision effects, and applies it to giant resonance phenomena.

Findings

LBUU method accurately reproduces nuclear ground states.

Full LBUU captures resonance widths with NN collisions.

Resonance width correlates with NN elastic cross section.

Abstract

We review the recent progress on studying the nuclear collective dynamics by solving the Boltzmann-Uehling-Uhlenbeck (BUU) equation with the lattice Hamiltonian method treating the collision term by the full-ensemble stochastic collision approach. This lattice BUU (LBUU) method has recently been developed and implemented in a GPU parallel computing technique, and achieves a rather stable nuclear ground-state evolution and high accuracy in evaluating the nucleon-nucleon (NN) collision term. This new LBUU method has been applied to investigate the nuclear isoscalar giant monopole resonances and isovector giant dipole resonances. While the calculations with the LBUU method without the NN collision term (i.e., the lattice Hamiltonian Vlasov method) describe reasonably the excitation energies of nuclear giant resonances, the full LBUU calculations can well reproduce the width of the giant dipole resonance of $^{208}$Pb by including a collisional damping from NN scattering. The observed strong correlation between the width of nuclear giant dipole resonance and the NN elastic cross section suggests that the NN elastic scattering plays an important role in nuclear collective dynamics, and the width of nuclear giant dipole resonance provides a good probe of the in-medium NN elastic cross section.