  We investigate a system consisting of a two-component Bose-Einstein
condensate interacting dispersively with a Fabry-Perot optical cavity where the
two components of the condensate are resonantly coupled to each other by
another classical field. The key feature of this system is that the atomic
motional degrees of freedom and the internal pseudo-spin degrees of freedom are
coupled to the cavity field simultaneously, hence an effective spin-orbital
coupling within the condensate is induced by the cavity. The interplay among
the atomic center- of-mass motion, the atomic collective spin and the cavity
field leads to a strong nonlinearity, resulting in multi- stable behavior in
both matter wave and light wave at the few-photon level.
