93 research outputs found
Nuclear descent from the fission barrier in the presence of long--range memory effects
We have investigated the peculiarities of nuclear descent from a parabolic
fission barrier within a generalized Langevin equation with power--law
memory function. We have observed much
stronger slowing down of the nuclear descent in the presence of long--range
memory effects, caused by the power--law memory function at , than
in the presence of short--range memory effects, generated by exponential
memory function. At a specific value of the
exponent of the power--law memory function, it turned out possible
to find analytically the trajectory of the descent and demonstrate that the
long--range memory effects give rise to complex time oscillations of nuclear
shape, becoming more frequent and damped with the correlation time . We
have found fairly long () times of the descent of at the values of the correlation time
A simple approach to the chaos-order contributions in nuclear spectra
The simple one-parameter nearest neighbor-spacing distribution (NNSD) is
suggested for statistical analysis of nuclear spectra. This distribution is
derived within the Wigner-Dyson approach in the linear approximation for the
level repulsion density of quantum states. The obtained NNSD gives the
individual information on the Wigner and Poisson contributions in agreement
with that of the statistical experimental distributions of collective states in
deformed nuclei. Using this NNSD, one finds that the symmetry breaking due to
the fixing of projections of the angular momentum of collective states enhances
a chaos as a shift of the NNSD from the Poisson to Wigner distribution
behavior.Comment: 6 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1711.0184
Collective motion in quantum diffusive environment
The general problem of dissipation in macroscopic large-amplitude collective
motion and its relation to energy diffusion of intrinsic degrees of freedom of
a nucleus is studied. By applying the cranking approach to the nuclear
many-body system, a set of coupled dynamical equations for the collective
classical variable and the quantum mechanical occupancies of the intrinsic
nuclear states is derived. Different dynamical regimes of the intrinsic nuclear
motion and its consequences on time properties of collective dissipation are
discussed.Comment: 15 pages, 5 figure
Non-Markovian large amplitude motion and nuclear fission
The general problem of dissipation in macroscopic large-amplitude collective
motion and its relation to energy diffusion of intrinsic degrees of freedom of
a nucleus is studied. By applying the cranking approach to the nuclear many
body system, a set of coupled dynamical equations for the collective classical
variables and the quantum mechanical occupancies of the intrinsic nuclear
states is derived. Different dynamical regimes of the intrinsic nuclear motion
and its consequences on time properties of collective dissipation are
discussed. The approach is applied to the descant of the nucleus from the
fission barrier.Comment: 9 pages and 3 figure
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