Dynamical entanglement in the model of field interacted with atoms of a nonlinear medium

The dynamical entanglement in a model of the field interacted with atoms in a nonlinear medium is studied in terms of concurrence and the reduced Neumann entropy for the generalized binomial state of the field and the ground state of atoms. It is shown that concurrence is dominantly-positively correlated with the reduced Neumann entropy. The entanglement under suitable condition is nearly unchanged for a long time. This is useful for quantum information processing.