A realizable multi-bit dense coding scheme with an Einstein–Podolsky–Rosen channel

We propose a multi-bit dense coding scheme by using only an Einstein-Podolsky-Rosen (EPR) channel and assistant qubits. It is shown that no matter how many classical bits there are, the quantum channel is always a Bell state. The present dense coding process can also prepare non-local multi-particle Greenberger-Horne-Zeilinger (GHZ) states at one of the participants. The quantum circuits for this dense coding process are constructed, the deterministic implementation method in an optical system based on the cross-Kerr nonlinearities is shown.