Spin mixing and protection of ferromagnetism in a spinor dipolar condensate

We study spin mixing dynamics in a chromium dipolar Bose-Einstein Condensate, after tilting the atomic spins by an angle \thetawith respect to the magnetic field. Spin mixing is triggered by dipolar coupling, but, once dynamics has started, it is mostly driven by contact interactions. For the particular case \theta=\pi/2 an external spin-orbit coupling term induced by a magnetic gradient is required to enable the dynamics. Then the initial...