Quantum Entanglement In The SU(1, 1)-related Coherent Fields Interacting With Two Two-level Atoms

In this paper, we study the entanglement properties of the correlated SU(1,1) coherent statevs light field interacting with a pair of two-level atoms via the resonant Raman interaction by means of full quantum theory. SU(1,1) coherent states has the predominant property in the entanglement of two modes, so in theory it can act as information carrier in quantum teleportation and is meaningful to study the interaction between SU(1,1) coherent states and atoms. Suppose that the distance between the atoms is less than the wavelength of the filed, and so dipole interaction between the atoms cannot be neglected. It is found that with the increase of the parameterξrepresenting the correlation of the two modes in the SU(1,1) coherent states, the atom-field entanglement is enhanced, but the atom-atom entanglement is weakened. On the other hand, the atom-atom couplingΩenhances the atom-atom entanglement, but tends to reduce the atom-field entanglement. The photon number difference between the two modes also has important effects on the entanglements. When the photon number difference is zero, the atom-field entanglement is smaller than that of other cases and the atom-atom entanglement keeps nearly its initial value for certain parameters.