摘要:
介绍了单
j壳的球形平均场加几何四极-四极和标准对力模型的量子相交叉行为。在单
j=15/2的壳内,计算了随模型控制参数变化的多个物理量如低激发能级、激发态间重叠积分、低激发态间的
B(E2)比值和电四极矩比值。结果显示,在类转动到对激发相的演化中,多个物理量在交叉区存在非常明显的变化,如
B(E2;4
1 → 2
1)/
B(E2;2
1 → 0
g),
B(E2;4
2 → 2
1)/
B(E2;2
1 → 0
g)等,并且这些变化在核子数达到半满壳时尤为显著。此外,尽管当
j较小时,由几何四极-四极相互作用得到的低激发能级不满足转动谱规律,但当
j值足够大时,这些低激发能级满足转动谱规律。
The analysis of the quantum phase crossover behavior in the spherical shell model mean-field plus the geometric quadrupole-quadrupole (
Q·
Q) and standard pairing model within a single-
j shell is reported. Several quantities, such as low-lying excitation energies, the overlaps of excited states, ratios of some
B(E2) and electric quadrupole moments of some low-lying states as functions of the control parameter of the model in a
j=15/2 shell are calculated. The results show that there are noticeable changes in the crossover region of the rotational-like to the pair-excitation phase transition, such as
B(E2;4
1 → 2
1)/
B(E2;2
1 → 0
g) and
B(E2;4
2 → 2
1)/
B(E2;2
1 → 0
g), especially in the half-filling case. Though the low-lying excitation energies generated from the geometric quadrupole-quadrupole interaction not satisfy the pattern of a rotational spectrum when
j is small, these energies follow the pattern of a rotational spectrum when
j is sufficiently large.