A scheme is reported for the teleportation of entangled coherent states through the degenerate Raman interaction. The scheme uses an entangled state of an atom and two coherent states as a quantum channel. It makes full use of coherent cavity fields. Furthermore, it does not need any classical field to transform the atom states.
A scheme is proposed to teleportation of an unknown multi-atom entangled state, considering the entangled states of two or more particles play an important role in both demonstrating quantum nonlocality and quantum information processing. The scheme is based on the degenerate Raman interaction of a Λ-type three-level atom with a single-mode field. First let n atoms cross a coherent cavity field in succession to prepare a quantum channel. Then the sender lets the other n atoms which carry the unknown state cross the cavity in succession and makes a joint measurement by detecting the cavity field and the atoms separately. When |α|1, the cavity field can be detected with the measurement method of detecting orthogonal states. Finally the receiver reconstructs the initial state according to the outcome of the joint measurement transmitted through a classical channel. The advantage of the scheme is that it uses an entangled state of a coherent state with n atoms as a quantum channel, which makes the scheme simple and easy. The scheme is expected to be useful in demonstrating quantum nonlocality and information processing.
We have proposed an alternative scheme for teleportation of two-atom entangled state in cavity QED. It is based on the degenerate Raman interaction of a single-mode cavity field with a ∧-type three-level atom. The prominent feature of the scheme is that only one cavity is required, which is prior to the previous one. Moreover, the atoms need to be detected are reduced compared with the previous scheme. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized for teleportation of N -atom GHZ entangled states. The number of the atoms needed to be detected does not increase as the number of the atoms in GHZ state increases.