Progress on relativistic symmetries by similarity renormalization group
LI DongPeng;GUO JianYou;School of Physics and Material Science, Anhui University;School of Electronic and Information Engineering, Hefei Normal University;
In the paper, we have outlined some progress on the researches of relativistic symmetries using the similarity renormalization group method and presented the theoretical details for the spherical and axially deformed nuclei. The Dirac Hamiltonian obtained from covariant density functional theory is transformed into a diagonal form, where the upper(lower) diagonal element becomes an operator describing the Dirac(anti-) particle. Every diagonal operator is made up of these components, which respectively correspond to the nonrelativistic term, the dynamical term, the spin-orbit interactions, the relativistic modification of kinetic energy, and the Darwin term. By using the operator, we have explored the origin and the broken mechanism of relativistic symmetries for the spherical and axially deformed nuclei. The results show that the breaking of spin symmetry almost completely is attributed to the spin-orbit interactions, while the pseudospin symmetry is related to the nonrelativistic term, the dynamical term and the spin-orbit coupling term.