Pairing Renormalization

Figure 2: Total energy (top) and neutron pairing gap (bottom) in $^{120}$Sn without (left) and with (right) pairing renormalization applied. Results are shown for volume (gray) and mixed (black) pairing. The total energy is plotted relative to the values obtained for the cutoff energy of $\epsilon_{\mbox{\rm\scriptsize{cut}}}$=60MeV.

Figure 2 illustrates the importance of the pairing renormalization procedure in the case of $^{120}$Sn. Due to the constraint (2) on the pairing strength, the neutron average pairing gap stays by definition constant, while the resulting total energy changes with the cutoff energy by a few hundred keV. On the other hand, without pairing renormalization applied, the total energy and the average neutron gap vary significantly with increasing dimension of the quasiparticle space. In this case, the total energy changes by several MeV.