Generalized time-dependent generator coordinate method for small and large amplitude collective motion

TL;DR

This paper develops a generalized time-dependent generator coordinate method (TD-GCM) for modeling small- and large-amplitude collective nuclear motions, integrating time-dependent mean-field trajectories with a collective wave function.

Contribution

It introduces a novel implementation of TD-GCM that combines time-dependent mean-field states with a collective wave function for nuclear dynamics.

Findings

Applied to giant resonances and induced fission dynamics

Demonstrated importance of pairing correlations in fission

Provided a framework for small- and large-amplitude motions

Abstract

An implementation of the generalized time-dependent generator coordinated method (TD-GCM) is developed, that can be applied to the dynamics of small- and large-amplitude collective motion of atomic nuclei. Both the generator states and weight functions of the GCM correlated wave function depend on time. The initial generator states are obtained as solutions of deformation-constrained self-consistent mean-field equations, and are evolved in time by the standard mean-field equations of nuclear density functional theory (TD-DFT). The TD-DFT trajectories are used as a generally non-orthogonal and overcomplete basis in which the TD-GCM wave function is expanded. The weights, expressed in terms of a collective wave function, obey a TD-GCM (integral) equation. In this explorative paper, the generalized TD-GCM is applied to the excitation energies and spreading width of giant resonances, and to the dynamics of induced fission. The necessity of including pairing correlations in the basis of TD-DFT trajectories is demonstrated in the latter example.