Dynamic versus static fission paths with realistic interactions

TL;DR

This paper compares dynamic and static fission paths using realistic interactions, showing that considering particle number fluctuations can significantly reduce action and improve lifetime predictions.

Contribution

It introduces a method to incorporate particle number fluctuations into fission path calculations, revealing substantial reductions in action and better alignment with experimental data.

Findings

Dynamic paths can have up to three times lower action than static paths.

Reduced action leads to significantly improved lifetime predictions.

Particle number fluctuations are crucial for accurate fission modeling.

Abstract

The properties of dynamic (least action) fission paths are analyzed and compared to the ones of the more traditional static (least energy) paths. Both the BCPM and Gogny D1M energy density functionals are used in the calculation of the HFB constrained configurations providing the potential energy and collective inertias. The action is computed as in the WKB method. A full variational search of the least-action path over the complete variational space of HFB wave functions is cumbersome and probably unnecessary if the relevant degrees of freedom are identified. In this paper, we consider the particle number fluctuation degree of freedom that explores the amount of pairing correlations in the wave function. For a given shape, the minimum action can be up a factor of three smaller than the action computed for the minimum energy state with the same shape. The impact of this reduction on the lifetimes is enormous and dramatically improves the agreement with experimental data in the few examples considered.