  We study the problem of two harmonically trapped atoms in the presence of
spin-orbital-angular-momentum coupling. The two-body energy spectrum is
numerically calculated by utilizing the exact diagonalization method. We
analyze how the degeneracy of energy levels is lifted under the interplay
between the interatomic interaction and spin-orbital-angular-momentum coupling.
The exact numerical results show an excellent agreement with that of
perturbation theory in the weak-interaction limit, as well as that in the
absence of spin-orbital-angular-momentum coupling. The properties of
correlations between the two atoms are also discussed with respect to the
interaction strength. The findings in this work may provide valuable insights
into few-body physics subjected to spin-orbital-angular-momentum coupling, and
the possible experimental detection of spectrum functions in many-body systems,
such as radio-frequency spectroscopy.
