Microscopic origin of the nuclear spin–orbit interaction

Determine the microscopic origin of the nuclear spin–orbit interaction in nuclear energy density functionals and effective nuclear interactions.

Background

The paper identifies the spin–orbit interaction as essential for reproducing magic numbers above 20, modeling dissipation in heavy-ion collisions, and predicting the location of the superheavy island of stability. Within the Skyrme framework, its strength and isovector dependence are represented phenomenologically through spin–orbit coupling parameters, whereas the quark–meson coupling model derives these contributions from relativistic and finite-size effects involving meson fields and Thomas precession.

Despite these theoretical descriptions, the paper states that the underlying microscopic origin of the nuclear spin–orbit interaction remains unsettled. Resolving this issue would clarify the physical basis of the spin–orbit terms used in nuclear energy density functionals and could improve predictions for shell structure and exotic nuclei.

References

Its microscopic origin is still debated .

— Skyrme-quark-meson-coupling energy density functional predictions to nuclear ground state properties  (2609.25664 - Mcrae et al., 22 Sep 2026) in Section 5, “Isovector dependence of the spin-orbit functional”