The time evolution of two coupling two-level atoms entanglement in a single-mode vacuum field is explored. The two-level atoms' reducible density matrix is obtained. The entangle ment between two two-level atoms is investigated by virtue of concurrence. The influences of the atomic dipole-dipole interaction on the entanglement of the two atoms are discussed. It is shown that the atomic dipole-dipole interaction leads to the decrease of the degrees of the entanglement and the increase of its time evolution period. In order to prepare entangled state, th...
