Formation of a Spin Texture in a Quantum Gas Coupled to a Cavity

We observe cavity mediated spin-dependent interactions in an off-resonantly driven multi-level atomic Bose-Einstein condensate that is strongly coupled to an optical cavity. Applying a driving field with adjustable polarization, we identify the roles of the scalar and the vectorial components of the atomic polarizability tensor for single and multi-component condensates. Beyond a critical strength of the vectorial coupling, we observe a spin...