Zr isotopes as a case study for intertwined quantum phase transitions

The scenario of intertwined quantum phase transitions (IQPTs) is identified in the Zr isotopes with neutron numbers 52 70, and shown to involve both a crossing of normal and intruder configurations and a shape-evolution within each configuration. Using the framework of the interacting boson model with configuration mixing, this situation is demonstrated by a quantum analysis of the spectra, E2 transition rates, order parameters, symmetry and configuration content of the wave functions and a classical analysis of energy surfaces.