Shell-model tests of the bimodal partial state densities in a 2 x 2 partitioned embedded random matrix ensemble

The mixing of well-separated subspacesof an interacting many-particle syste m,such as a nucleus with active nucleons distributed in more than one major shell,can be studied usingpartitioned embedded ensembles of random matrice s. The bimodalform of partial state densities (one-point functions) predict edearlier for a 2 x 2 partitioned embedded ensemble, whichmay be regarded a s a model for the mixing of two well-separated degeneratesubspaces, is test ed using nuclear shell-model calculations in the [(ds)(6) + (ds)(4) (f(7/2) )(2)](J=0,T=0) space. Thetheoretical forms predicted by the binary correlat ionapproximation theory are in good agreement with the shell-modelresults. This suggests that with suitable extensions it might be feasibleto use the binary correlation method to deal with severalinteracting subspaces involvi ng multimodal distributions.