A scheme is presented for preparing multi-cavity fields Schrdinger cat states via cavity QED. In this scheme, a single two-level atom is sent through N identical single-mode cavities, and the atom interacts with the N acvitiy fields simultaneously. It is based on the Jaynes-Cummings model with a large detuning.
In the context of cavity quantum electrodynamics (QED),a potential scheme is proposed to generate entangled coherent states. The scheme includes twice interactions of two-level atoms with cavities. In the first interaction,two atoms are sent into a microwave cavity with the large detuning respectively. And then the second interaction is that the two atoms enter another microwave cavity and are driven by a resonant classical field meantime. When we choose the proper interaction time and make measurement on the two atoms,the two microwave cavity mode fields are determinatively entangled. In addition,it is easy to generalize the scheme to multi-cavity and multi-atom.
A scheme is proposed for the generation of superpositions of multi-mode coherent states, i.e. multi-mode Schrödinger cat states. In the scheme a -type three-level atom is sent through many cavities filled with coherent fields. The whole system is entangled via the Raman atom-field interaction. Then the detection of the atom leaves the cavity system in a multi-mode cat state. Under certain conditions, such a cat state is identical to a Greenberger-Horne-Zeilinger state and thus can be used to test local realistic theories.
An experimentally feasible scheme for implementing teleportation of multi-atom cat-like states in cavity QED is proposed. In the scheme the atoms interact simultaneously with a highly detuned cavity mode and are driven by a strong classical field, and the atomic state evolution is independent of cavity field state. Thus the scheme is insensitive to both the cavity decay and the thermal field, which is of importance from the experimental point of view. All the orthogonal and complete multi-atom GHZ states can be exactly distinguished only by one step, so our scheme can also be used for other purposes such as dense coding using multi-atom GHZ states as quantum channels.