标题： 变分方法在核壳模型计算中对称恢复准粒子基态叠加的运用 显示英文标题

标题： Variational approach with the superposition of the symmetry-restored quasi-particle vacua for nuclear shell-model calculations

摘要： 我们提出了一种变分计算方案，利用角动量、宇称、数投影准粒子基态的叠加，这特别适用于壳模型计算中的中重核。我们推导了准粒子基态能量方差的公式，并将能量方差外推应用于当前方案，以进一步精确估计精确的壳模型能量。该方法的有效性通过在$50 \leq Z,N \leq 82$模型空间中$^{132}$Ba的壳模型计算来展示。我们还讨论了在$50 \leq Z \leq 82$和$82 \leq Z \leq 126$模型空间中$^{150}$Nd的情况下此方案的可行性，并证明其无中微子双贝塔衰变矩阵元表现出良好的收敛性。 显示英文摘要

摘要： We propose a variational calculation scheme utilizing the superposition of the angular-momentum, parity, number projected quasiparticle vacua, that is especially suitable for applying to medium-heavy nuclei in shell-model calculations. We derive a formula for the energy variance with quasi-particle vacua and apply the energy-variance extrapolation to the present scheme for further precise estimation of the exact shell-model energy. The validity of the method is presented for the shell-model calculation of $^{132}$Ba in the $50 \leq Z,N \leq 82$ model space. We also discuss the feasibility of this scheme in the case of the $^{150}$Nd in the $50 \leq Z \leq 82$ and $82 \leq Z \leq 126$ model space and demonstrate that its neutrinoless-double-beta-decay matrix element is obtained showing good convergence.