The peculiarities of descent of the nucleus from the fission barrier are investigated within the generalized Langevin equation with the power-law memory function $f(t-t^{\prime })=\left(\right|t-t^{\prime }{|/\tau )}^{-\alpha }$. It is observed that there is much stronger slowing down of the descent in the presence of long-range memory effects, caused by the power-law memory function at $0<\alpha <1$, than of short-range memory effects, generated by the exponential memory function $f(t-t^{\prime })=exp(-|t-t^{\prime }|/\tau )$. At a specific value of the exponent $\alpha =1/2$ of the power-law memory function, it becomes possible to find analytically the trajectory of descent and demonstrate that the long-range memory effects give rise to complex time oscillations of nuclear shape. One found fairly long $(>{10}^{-20}\mathrm{s})$ times of descent of ${}^{236}\mathrm{U}$ at the correlation times $\tau \in [{10}^{-24},{10}^{-22}]\mathrm{s}$.

• Received 3 September 2023
• Revised 31 October 2023
• Accepted 20 December 2023

DOI:https://doi.org/10.1103/PhysRevC.109.024320