Domain-wall solutions of spinor Bose-Einstein condensates in an optical lattice

We studied the static and dynamic domain-wall solutions of spinor Bose-Einstein condensates trapped in an optical lattice. The single and double domain-wall solutions are constructed analytically. Our results show that the magnetic field and light-induced dipolar interactions play important roles for both the formation of different domain walls and the adjusting of domain-wall width and velocity. Moreover, these interactions can drive the motion of the domain wall in Bose ferromagnet systems similar to the way the external magnetic field or the spin-polarized current drives it in fermion ferromagnets.