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Z. Z. Qin

Publications and source records attributed to Z. Z. Qin.

4 recordsLinked to original sources
arXiv2024

The pervasiveness of shape coexistence in nuclear pair condensates

We investigate nuclear shape coexistence for a wide range of even-even nuclides. By varying general pair condensates, which include Slater determinants as a limit but also allow for arbitrary pairing channels, we frequently find multiple coexisting mimina, and often more than two. This is consistent with recent experimental results. In order to measure general pairwise correlations beyond a simple Slater determinant, we introduce a novel entropy-like measure, which is smallest mid-shell and largest near shell closures; this is consistent with a picture of pairing-like behavior dominating near closed shells and deformation mid-shell. After surveying nuclides spanning from the $sd$ shell to nuclides between magic numbers 50 and 82, we focus on the six lightest nuclei with shape coexistence. Angular-momentum projected variational pair condensate (PVPC) calculations identify band structures, including two newly proposed coexisting bands in $^{26}$Si/Mg and $^{24}$Si/Ne. The PVPC results agree well with data, providing robust experimental support for the pervasiveness of coexistence in these light nuclei.

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arXiv2024

Robust correlation between binding energies and charge radii of mirror nuclei

Using the charge density from the two-parameter Fermi model, a robust and nontrival correlation between binding energis and charge radii of mirror nuclei is newly proposed. This correlation enables simple yet reliable predictions of the nuclear mass and charge radius of proton-rich nuclei. The validity of these predictions is demonstrated by comparing the predicted binding energies and charge radii with experimental data and predictions from other models. All 197 predicted binding energies and 199 charge radii involved in the comparisons are tabulated in the Supplemental Materials of this paper. The noticeable discrepancies are attributed to the large asymmetry in charge densities of mirror nuclei, suggesting that the proposed correlation could be a sensitive probe for local structural anomaly, such as shell closure and proton halo. The difference in mass dependence of charge radii near the proton dripline compared to those along the $β$-stability line supports the validity of our prediction method.

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arXiv2016

Global correlations between electromagnetic and spectroscopic properties of collective $2^+_1$ and $2^+_2$ states

By using the general triaxial rotor model (TRM) and the phonon-configuration mixing scheme within an anharmonic-vibrator(AHV) framework, a series of global correlations between electromagnetic properties of nuclear $2^+_1$ and $2^+_2$ states are analytically established. The correlations from both models can roughly describe the experimental data involving quadrupole collectivity with few exceptions. Furthermore, there seems to be a robust orthogonal transformation between the AHV and TRM bases for realistic nuclear systems, suggesting that the two models may in fact be describing the collective features of nuclear low-lying states in similar model spaces.

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