Abstract

FOSSION, R.. Signatures for shape-phase transitions in the rare-earth nuclei, in the evolution of single-particle spectra and two-particle transfer-intensities. Rev. mex. fis. [online]. 2008, vol.54, suppl.3, pp.42-47. ISSN 0035-001X.

The rare-earth Nd, Sm, Gd and Dy nuclei are well known to undergo a shape-phase transition around N 90 from vibrational to rotational behaviour - or, correspondingly - from a spherical nuclear shape to an axial-symmetric deformed shape. This can experimentally be verified by, for example, the evolution of the R_4/2= E(4⁺₁) / E (2⁺₁) ratio, or the evolution of the quadrupole moment, Q₂. Recently, the study of nuclear phase-shape transitions has gained considerable interest, since the introduction of exact algebraic solutions for the critical points of many of the different phase-shape transitions that are possible in the atomic nucleus. In this contribution, in the first part, we investigate the microscopic underlying mechanism that drives the rare-earth isotopes towards deformation, studying the evolution of their proton and neutron single-particle spectra within the Relativistic Hartree-Bogoliubov model. In the second part, within the Interacting Boson Model and the framework with boson coherent states, and in the light of renewed interest in experiments on two-particle transfer-reactions, we study the evolution of the transfer spectroscopic intensities as a possible signature of shape-phase transitions.

Keywords : Nuclear structure models and methods; quantum phase transitions.

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