  In this paper, firstly, we consider bipartite entanglement between each part
of an optomechanical cavity composed of one dimensional Bose-Einstein
condensate (BEC). we investigate atomic collision on the behavior of the BEC in
the week photon-atom coupling constant, and use Bogoliubov approximation for
the BEC. Secondly under above condition, we propose a scheme for entanglement
swapping protocol wich involves tripartite systems. In our investigation, we
consider a scenario where BECs, moving mirrors, and optical cavity modes are
given in a Gaussian state with a covariance matrix (CM). By applying the Bell
measurment to the output optical field modes, we show how the remote
entanglement between two BECs, two moving mirrors, and BEC-mirror modes in
different optomechanical cavity can be generated.
