Vortex patterns in rotating dipolar Bose–Einstein condensate mixtures with squared optical lattices

Abstract

Vortex-lattice patterns with transitions from regular to other variety vortex shapes are predicted in rotating binary mixtures of dipolar Bose–Einstein condensates loaded in squared optical lattices (OLs). We focus our investigation on the experimentally accessible dipolar isotopes of dysprosium (162,164Dy), erbium (168Er), chromium (52Cr), and rubidium (87Rb), by considering the binary mixtures (164Dy-162Dy, 168Er-164Dy, 164Dy-52Cr and 164Dy-87Rb), which are confined in strong pancake-shaped traps and loaded in squared two-dimensional (2D) OLs, where we vary the polarization angle of the dipoles, the inter-species contact interactions and the rotation frequency. The ratio between inter- to intra-species contact interaction is used for altering the miscibility properties, with the polarization of the dipolar species used for tuning the dipole–dipole interactions to repulsive or attractive. For enough higher rotation, where the inter- to intra-species scattering length ratio is larger than one, in which a richer variety of vortex-lattice patterns are predicted, including vortex sheets and 2D rotating droplet formations. The patterns can be controlled by changing the OL parameters, as shown for the symmetric 164Dy-162Dy dipolar mixture. For mixtures with stronger differences in the dipole moments, such as 164Dy-52Cr and 164Dy-87Rb, only half the quantum vortices and circular ones have been observed, which will depend on the dipole orientations.