Breakdown of the tensor component in the Skyrme energy density functional

Abstract

The tensor force, as an important component of strong nuclear force, generates a variety of intriguing effects ranging from few-body systems to neutron stars. It is responsible for the nucleon-nucleon correlation beyond mean-field approximation, and is accordingly proved to play no role in the standard Skyrme energy density functionals in the present work. Therefore, the Skyrme's original tensor interaction that is extensively-employed presently is invalid. As an alternative strategy, we introduced a central interaction, i.e., the $\bm{σ}_{1}\cdot \bm{σ}_{2}$ term, to improve the description of experimental single-particle structure, and to address its effect, we established two Skyrme interactions IMP1 and IMP2 complemented by the calibrated charge-violating interactions. The central $\bm{σ}_{1}\cdot \bm{σ}_{2}$ interaction turns out to substantially improve the description of shell evolution in Sn isotopes and $N=82$ isotones.