Incompressibility of finite fermionic systems: Stable and exotic atomic nuclei

The incompressibility of finite fermionic systems is investigated using analytical approaches and microscopic models. The incompressibility of a system is directly linked to the zero-point kinetic energy of constituent fermions, and this is a universal feature of fermionic systems. In the case of atomic nuclei, this implies a constant value of the incompressibility in medium-heavy and heavy nuclei. The evolution of nuclear incompressibility along Sn and Pb isotopic chains is analyzed using global microscopic models, based on both nonrelativistic and relativistic energy functionals. The result is an almost constant incompressibility in stable nuclei and systems not far from stability and a steep decrease in nuclei with pronounced neutron excess, caused by the emergence of a soft monopole mode in neutron-rich nuclei.

Figure 1

Nuclear incompressibility of the Sn and Pb isotopic chains, calculated using the microscopic Skyrme-CHFB method (circles), the Skyrme-QRPA (triangles), and the relativistic QRPA (squares).

Figure 2

Isoscalar monopole response in Sn isotopes, calculated using the relativistic QRPA with the DD-ME2 functional (solid) and the QRPA with the functional SLy5 (dashed). The response is folded with a Lorentzian of 1 MeV width.

Figure 3

Same as described in the caption to Fig. 2 but for the Pb isotopes.

Figure 4

Nuclear incompressibility in the Sn isotopic chain calculated using the microscopic Skyrme-QRPA with the functional SLy5. (a) Total nuclear incompressibility $K_A$. (b) Values determined by the monopole response in the low-energy region. (c) Values for the GMR region.

Figure 5

Same as described in the caption to Fig. 4 but for the Pb isotopes.