6 research outputs found
Is friction responsible for the reduction of fusion rates far below the Coulomb barrier?
The fusion of two interacting heavy ions traditionally has been interpreted
in terms of the penetration of the projectile into the target. Observed rates
well below the Coulomb barrier are considerably lower than estimates obtained
from penetration factors. One approach in the analysis of the data invokes
coupling to non-elastic channels in the scattering as the source of the
depletion. Another is to analyze those data in terms of tunneling in
semi-classical models, with the observed depletion being taken as evidence of a
``friction'' under the barrier. A complementary approach is to consider such
tunneling in terms of a fully quantal model. We investigate tunneling with both
one-dimensional and three-dimensional models in a fully quantal approach to
investigate possible sources for such a friction. We find that the observed
phenomenon may not be explained by friction. However, we find that under
certain conditions tunneling may be enhanced or diminished by up to 50%, which
finds analogy with observation, without the invocation of a friction under the
barrier.Comment: 18 pages, 15 figures embedde
Open problems in nuclear density functional theory
This note describes five subjects of some interest for the density functional
theory in nuclear physics. These are, respectively, i) the need for concave
functionals, ii) the nature of the Kohn-Sham potential for the radial density
theory, iii) a proper implementation of a density functional for an "intrinsic"
rotational density, iv) the possible existence of a potential driving the
square root of the density, and v) the existence of many models where a density
functional can be explicitly constructed.Comment: 10 page