Intrinsic quartet states and band-like structures in

The band structure of $$N=Z$$ nuclei is constructed by projecting states of good angular momentum from intrinsic states defined in terms of quartets. The simplest of these intrinsic states is a condensate of collective quartets with isospin $$T=0$$. The other intrinsic states are built by promoting one quartet of the condensate to an excited $$T=0$$ configuration. From these intrinsic states, by angular momentum projection, band structures are generated that approximate well the experimental ones. The projected states also reproduce to a very good extent the spectra resulting from configuration interaction calculations based on the same quartets forming the intrinsic states. These results show that the quartet-based intrinsic states provide an appropriate framework to understand in a simple and intuitive manner the emergence of band-like structures in $$N=Z$$ nuclei