| Quantum entangled states play an incomparable role in quantum cryptography and quantum teleportation. For quantum communication, quantum channels can be built between two communicating parties and implementing the classical communication technology, in order to fulfill the aim of communicating of two parties. Entangled state is of great significance to such as quantum cryptography, quantum teleportation, calculation and communication. Thus entanglement measurement is a very important theoretical subject to the study of entanglement.In this paper, we adopt the system of single atom interacting with multi-cavities as our research subject, through which we emphasis the feature of entanglement among cavities. In our system, cavities have no direct interactions with each other, but are connected via atoms which carry the information of cavities as a medium. We analyze the entanglement feature among cavities by adopting the concurrence which can effectively measure the interaction behaviors between two bits.In the system of single atom coupled with two cavities, the entanglement of the two cavities changes with time, couple strength, the frequency detuning between the cavity mode and atom’s transitions. In most circumstances, the degree of entanglement shows periodical oscillation. When the relation between the frequency of the cavity and atom transition show large detuning, the result shows the changes of amplitudes agree with the theoretical analysis of the feature of large detuning. Moreover, the entanglement purification of two cavities are carefully analyzed and calculated. It appears that in this kind of interacting system, the two cavities’ entanglement purification based on Bell base can be realized. Furthermore, the entanglement between cavities under the condition of single atom coupled with three cavities and four cavities are discussed in this paper as well. In our analysis, the specific initial state is adopted so that each cavity can be regarded as a single quantum bit. |
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