Generation correlated four-mode states in cavity QED

A scheme for preparing correlated four-mode states with controllable weighting factors is presented. In the scheme, a sequence of suitably prepared four-level atoms are orderly sent through two bimodal cavities, the detection of all atoms in ground state collapses cavity fields to the desire state. The distinct advantage of our scheme is that the interaction time can be greatly shortened, which is important in view of decoherence.