Abstract
In this communication, we consider a pair of entangled quantum systems, each described by the
su
(
1
) Lie algebra, interacting with two two-level atoms. We discuss in detail the influence of the detuning terms on the system and derive from the Heisenberg equations of motion the expressions of various operators corresponding to the dynamics. Solving the associated Schrödinger equation, we obtain the general solution. Then we calculate and discuss in detail the expression of the von Neumann entropy for the two qubits and the radiation field. We examine the negativity index to gauge the degree of quantum entanglement between the
su
(1) quantum system and the atoms. Finally, we compare the results of the negativity and von Neumann entropy for some values of the initial state and the detuning parameter.