In this paper, we prove the existence of
the ground state for the spinor Bose-Einstein condensates with the
external Ioffe-Pitchard magnetic field in the one-dimensional
case. We also characterize the ground states of spin-1
Bose-Einstein condensates with the external Ioffe-Pitchard
magnetic field, i.e., for ferromagnetic systems, we show that
under some condition, searching for ground state of ferromagnetic
spin-1 BEC with the external Ioffe-Pitchard magnetic field can be
reduced to a one-component minimization problem.
10.1017/S0004972712000305
Abstract In this paper, we prove the existence of the ground state for the spinor Bose–Einstein condensates with an external Ioffe–Pitchard magnetic field in the one-dimensional case. We also characterise the ground states of spin-1 Bose–Einstein condensates with an external Ioffe–Pitchard magnetic field; that is, for ferromagnetic systems, we show that, under some condition, searching for the ground state of ferromagnetic spin-1 Bose–Einstein condensates with an external Ioffe–Pitchard magnetic field can be reduced to a ‘one-component’ minimisation problem.
In this paper, we systematically review mathematical models, theories and numerical methods for ground states and dynamics of spinor Bose-Einstein condensates (BECs) based on the coupled Gross-Pitaevskii equations (GPEs). We start with a pseudo spin-1/2 BEC system with/without an internal atomic Josephson junction and spin-orbit coupling including (i) existence and uniqueness as well as non-existence of ground states under different parameter regimes, (ii) ground state structures under different limiting parameter regimes, (iii) dynamical properties, and (iv) efficient and accurate numerical methods for computing ground states and dynamics. Then we extend these results to spin-1 BEC and spin-2 BEC. Finally, extensions to dipolar spinor systems and/or general spin-F (F>=3) BEC are discussed.