  In this paper, we investigate the non-equilibrium quantum phases of the
two-atom Dicke model, which can be realized in a two species Bose-Einstein
condensate interacting with a single light mode in an optical cavity. Apart
from the usual non-equilibrium normal and inverted phases, a non-equilibrium
mixed phase is possible which is a combination of normal and inverted phase. A
new kind of quantum phase transition is predicted from non-superradiant mixed
phase to the superradiant phase which can be achieved by tuning the two
different atom-photon couplings. We also show that a quantum phase transition
from the non-superradiant mixed phase to the superradiant phase is forbidden
for certain values of the two atom-photon coupling strengths.
