Quantum fluctuations in the collective 0+ states of deformed nuclei

The occurrence of low-energy collective motion is a widespread phenomenon in quantum systems. To describe fluctuations about the equilibrium deformation and to understand the nature of excited 0(+) states in deformed nuclei, we improve the many-body wave functions by superimposing angular-momentum-projected states constructed with different quadrupole deformations. We take deformed rare-earth nuclei as examples, compare quantitatively the calculated low-lying 0(+) bands and the associated electric monopole transition matrix elements with experimental data. The analysis of the resulting wave functions for the excited 0(+) states indicates clear features of quantum oscillations, with large fluctuations in deformation for soft nuclei and strong anharmonicities in the oscillations for rigidly deformed nuclei.