Memory effects in Langevin approach to the nuclear fission process

TL;DR

This paper investigates how memory effects influence the fission width in nuclear processes using a Langevin approach, highlighting the significance of quantum fluctuations and the impact of effective temperature at low excitation energies.

Contribution

It introduces a simplified one-dimensional Langevin model to analyze memory effects on fission width, emphasizing the importance of quantum fluctuations and effective temperature.

Findings

Memory effects influence fission width oppositely at low energies.

Effective temperature significantly affects diffusion coefficient calculations.

Fission widths at very low energies are overestimated without proper modeling.

Abstract

We present the schematic calculations within the Langevin approach in order to investigate the dependence of fission width on the memory time and the excitation energy at low temperatures where the quantum fluctuations play an important role. For this we consider the simple one-dimensional case with the potential energy given by two parabolic potentials (Kramers potential). For friction and the mass parameters we use the deformation independent values fitted to the results obtained earlier within the microscopic linear response theory. We have found out that at small excitation energies (comparable with the fission barrier height) the memory effects in the friction and random force acts on the fission width in opposite direction. The total effect is not so large, but still quite noticeable (depending on the value of the relaxation time). The use of effective temperature in the diffusion coefficient turns out to be much more important compared with the memory effects. The calculated fission width at very low excitation energies is unrealistically too big.