Magnetic properties of a spin-3 chromium condensate

We study the ground-state properties of a spin-3 Cr condensate subject to an external magnetic field by numerically solving the Gross-Piteavskii equations. We show that the widely adopted single-mode approximation is invalid under a finite magnetic field. In particular, a phase separationlike behavior may be induced by the magnetic field. We also point out the possible origin of the phase separation phenomenon.