Interplay between shell structure and trap deformation in dipolar fermi gases

Abstract: Finite fermion systems are known to exhibit shell structure in the weakly-interacting regime, as well known from atoms, nuclei, metallic clusters or even quantum dots in two dimensions. All these systems have in common that the particle interactions between electrons or nucleons are spatially isotropic. Dipolar quantum systems as they have been realized with ultra-cold gases, however, are governed by an intrinsic anisotropy of the two-body interaction that depends on the orientation of the dipoles relative to each other. Here we investigate how this interaction anisotropy modifies the shell structure in a weakly interacting two-dimensional anisotropic harmonic trap. Going beyond Hartree-Fock by applying the so-called "importance-truncated" configuration interaction (CI) method as well as quadratic CI with single- and double-substitutions, we show how the magnetostriction in the system may be counteracted upon by a deformation of the isotropic confinement, restoring the symmetry.