  We study the multipartite correlations of the multi-atom dark states, which
are characterized by the atomic squeezing beyond the pairwise entanglement. It
is shown that, in the photon storage process with atomic ensemble via
electromagnetically induced transparency (EIT) mechanism, the atomic squeezing
and the pairwise entanglement can be created by adiabatically manipulating the
Rabi frequency of the classical light field on the atomic ensemble. We also
consider the sudden death for the atomic squeezing and the pairwise
entanglement under various decoherence channels. An optimal time for generating
the greatest atomic squeezing and pairwise entanglement is obtained by studying
in details the competition between the adiabatic creation of quantum
correlation in the atomic ensemble and the decoherence that we describe with
three typical decoherence channels.
