### Speaker

Yang Sun

### Description

In performing shell-model calculations for large nuclear
systems, the central issue is how to truncate the
shell-model space efficiently. It corresponds to a proper
arrangement of the configuration space to separate the most
important part from the rest of the space. There are
different schemes for the shell-model truncation.
Considering the fact that most nuclei in the nuclear chart
are deformed, using a deformed basis supplemented by angular
momentum projection is an efficient way. Shell-model
Hamiltonian is then diagonalized in the projected basis. The
method is in principle independent of how a deformed basis
is prepared and how an effective interaction is chosen.
This approach may be viewed as to bridge the two traditional
nuclear physics methods: the deformed mean-field
approximation and the conventional shell-model
diagonalization, because it keeps all the advantages that a
mean-field model has to incorporate important correlations,
and has the properties of the conventional shell-model that
configurations are mixed beyond the mean-filed states to
include effects of residual interactions.
In this talk, we present the above idea by taking the
Projected Shell Model and its extensions as examples
[1,2,3,4]. Given the strong demand for shell model
calculations also from nuclear astrophysics, one needs such
an approach that contains sufficient correlations and can
generate wave functions in the laboratory frame, thus
allowing exact calculations for transition probabilities,
spectroscopic factors, and beta-decay and electron-capture
rates, in heavy, deformed nuclei.
This research is supported by the National Natural Science
Foundation of China (No. 11135005) and by the 973 Program of
China (No. 2013CB834401).
[1] K. Hara, Y. Sun, Int. J. Mod. Phys. E4 (1995) 637.
[2] Y. Sun and C.-L. Wu, Phys. Rev. C68 (2003) 024315.
[3] Y. Sun, Int. J. Mod. Phys. E15 (2006) 1695.
[4] Y. Sun, Rev. Mex. Fis. S54(3) (2008) 122.