摘要
We study a mixture of s-bosons and like-nucleon pairs with the standard pairing interaction outside an inert core. Competition between the nucleon-pairs and s-bosons is investigated in this scenario. The robustness of the BCS-BEC coexistence and crossover phenomena are examined through an analysis of pf-shell nuclei with realistic single-particle energies, in which two configurations with Pauli blocking of nucleon-pair orbits due to the formation of the s-bosons is taken into account. When the nucleon-pair orbits are considered to be independent of the s-bosons, the BCS-BEC crossover becomes smooth, with the number of the s-bosons noticeably more than that of the nucleon-pairs near the half-shell point, a feature that is demonstrated in the pf-shell for several values of the standard pairing interaction strength. As a further test of the robustness of the BCS-BEC coexistence and crossover phenomena in nuclei, results are given for B（E2; 01^＋→21^＋） values of even-even ^102-130 Sn with ^100Sn taken as a core and valence neutron pairs confined within the 1d（5/2）, 0g（7/2）, 1d（3/2）, 2s（1/2）, 1h（11/2）orbits in the nucleon-pair orbit and the s-boson independent approximation. The results indicate that the B（E2） values are reproduced well.
We study a mixture of s-bosons and like-nucleon pairs with the standard pairing interaction outside an inert core. Competition between the nucleon-pairs and s-bosons is investigated in this scenario. The robustness of the BCS-BEC coexistence and crossover phenomena are examined through an analysis of pf-shell nuclei with realistic single-particle energies, in which two configurations with Pauli blocking of nucleon-pair orbits due to the formation of the s-bosons is taken into account. When the nucleon-pair orbits are considered to be independent of the s-bosons, the BCS-BEC crossover becomes smooth, with the number of the s-bosons noticeably more than that of the nucleon-pairs near the half-shell point, a feature that is demonstrated in the pf-shell for several values of the standard pairing interaction strength. As a further test of the robustness of the BCS-BEC coexistence and crossover phenomena in nuclei, results are given for B（E2; 01^＋→21^＋） values of even-even ^102-130 Sn with ^100Sn taken as a core and valence neutron pairs confined within the 1d（5/2）, 0g（7/2）, 1d（3/2）, 2s（1/2）, 1h（11/2）orbits in the nucleon-pair orbit and the s-boson independent approximation. The results indicate that the B（E2） values are reproduced well.
基金
Supported by National Natural Science Foundation of China(11375080,11675071)
the U.S. National Science Foundation(OCI-0904874 and ACI-1516338)
U.S. Department of Energy(DE-SC0005248)
the Southeastern Universities Research Association,the China-U.S. Theory Institute for Physics with Exotic Nuclei(CUSTIPEN)(DE-SC0009971)
the LSU–LNNU joint research program(9961)
