Clustering phenomena in nuclear matter below the saturation density

We investigate density-fluctuated states of nuclear matter as a result of clustering below the saturation density rho(0) by description in terms of the Bloch function. The Bloch description has the advantage of a unified representation for a density-fluctuated state from an aggregate of uncorrelated clusters in extremely low-density regions to the plane-wave state of uniform matter in relatively high-density regions. We treat the density-fluctuated states due to alpha and O-16 clustering in symmetric nuclear matter and due to He-10 clustering in asymmetric nuclear matter. The density-fluctuated states develop as the density of matter decreases below each critical density around 0.2-0.4 rho(0) which depends on what kind of effective force we use.