Nucleon-pair approximation with uncoupled representation * *Support by the Sichuan Science and Technology Program (2019JDRC0017), Doctoral Program of Southwest University of Science and Technology (18zx7147), National Natural Science Foundation of China (11705100), Youth Innovations and Talents Project of Shandong Provincial Colleges, and Universities (201909118), Higher Educational Youth Innovation Science and Technology Program Shandong Province (2020KJJ004), National Natural Science Foundation of

Abstract

In this paper, we propose an approach to nucleon-pair approximation (NPA) with m-scheme bases, in which the collective nucleon pairs are represented in terms of antisymmetric matrices, and commutations between nucleon pairs are given using a matrix multiplication that avoids angular-momentum couplings and recouplings. Therefore the present approach significantly simplifies the NPA computation. Furthermore, it is formulated on the same footing with and without isospin.