  It was shown in Ref.[Phys.Rev.A 77,045802(2008)] that the dynamics of a
control atom and an atomic sample interacting dispersively with a cavity can be
discribed by the Jaynes-Cummings model and the collective mode of the atomic
sample can be analogous with a bosonic mode. Here, by analogizing the behaviour
of the atomic sample with the one of the cavity, we propose a scheme to
generate cluster states of atomic ensembles by Cavity QED.
