Superfluid-Mott Insulator Transition of Spin-2 Cold Bosons in an Optical Lattice in a Magnetic Field

The superfluid-Mott insulator transition of spin-2 boson atoms with repulsive interaction in an optical lattice in a magnetic field is presented. By using the mean field theory, Mott ground states and phase diagrams of superfluid-Mott insulator transition at zero temperature are revealed. Applied magnetic field leads to some phase boundaries splitting. For all the initial Mott ground states containing multiple spin components, different spin components take on different phase boundaries. It is found that in this system the phase boundaries with different magnetization can be moved in different ways by only changing the intensity of the applied magnetic field.