Resonant demagnetization of a dipolar BEC in a 3D optical lattice
  We study dipolar relaxation of a chromium BEC loaded into a 3D optical lattice. We observe dipolar relaxation resonances when the magnetic energy released during the inelastic collision matches an excitation towards higher energy bands. A spectroscopy of these resonances for two orientations of the magnetic field provides a 3D band spectroscopy of the lattice. The narrowest resonance is registered for the lowest excitation energy. Its line-shape is sensitive to the on-site interaction energy. We use such sensitivity to probe number squeezing in a Mott insulator, and we reveal the production of three-body states with entangled spin and orbital degrees of freedom. 
A. de Paz, A. Chotia, E. Marechal, P. Pedri, L. Vernac, O. Gorceix and   B. Laburthe-Tolra
cond-mat.quant-gas