4 research outputs found
Instabilities in the Nuclear Energy Density Functional
In the field of Energy Density Functionals (EDF) used in nuclear structure
and dynamics, one of the unsolved issues is the stability of the functional.
Numerical issues aside, some EDFs are unstable with respect to particular
perturbations of the nuclear ground-state density. The aim of this contribution
is to raise questions about the origin and nature of these instabilities, the
techniques used to diagnose and prevent them, and the domain of density
functions in which one should expect a nuclear EDF to be stable.Comment: Special issue "Open Problems in Nuclear Structure Theory" of
Jour.Phys.G - accepted. 7 pages, 2 figure
Linear response strength functions with iterative Arnoldi diagonalization
We report on an implementation of a new method to calculate RPA strength
functions with iterative non-hermitian Arnoldi diagonalization method, which
does not explicitly calculate and store the RPA matrix. We discuss the
treatment of spurious modes, numerical stability, and how the method scales as
the used model space is enlarged. We perform the particle-hole RPA benchmark
calculations for double magic nucleus 132Sn and compare the resulting
electromagnetic strength functions against those obtained within the standard
RPA.Comment: 9 RevTeX pages, 11 figures, submitted to Physical Review
Error analysis of nuclear mass fits
We discuss the least-square and linear-regression methods, which are relevant
for a reliable determination of good nuclear-mass-model parameter sets and
their errors. In this perspective, we define exact and inaccurate models and
point out differences in using the standard error analyses for them. As an
illustration, we use simple analytic models for nuclear binding energies and
study the validity and errors of models' parameters, and uncertainties of its
mass predictions. In particular, we show explicitly the influence of
mass-number dependent weights on uncertainties of liquid-drop global
parameters.Comment: 10 RevTeX pages, 9 figures, submitted to Physical Review