Anisotropic optical trapping of ultracold erbium atoms

摘要: Ultracold atoms confined in a dipole trap are submitted to potential whose depth is proportional the real part of their dynamic polarizability. The also experience photon scattering rate imaginary In this article we calculate complex polarizability ground-state erbium, rare-earth atom that was recently Bose condensed. calculated with sum-over-state formula inherent second-order perturbation theory. summation performed on transition energies and moments from which computed using Racah-Slater least-squares fitting procedure provided by cowan codes. This allows us predict nine unobserved odd-parity energy levels total angular momentum $J=5$, 6, 7, range 25 000--31 000 cm${}^{\ensuremath{-}1}$ above ground state. Regarding trapping potential, find erbium essentially behaves like spherically symmetric atom, spite its large electronic momentum. We mostly isotropic van der Waals interaction between two atoms, characterized coefficient ${C}_{6}^{\mathrm{iso}}=1760$ a.u. To contrary, photon-scattering shows pronounced anisotropy since it strongly depends polarization light.