A relaxation process including interaction effects of a two-qubit system

A relaxation process of a two-qubit system is studied by means of the quantum master equation. The two qubits interact with each other via the Ising-type coupling, and one of the two qubits is placed under the influence of a thermal reservoir and the other is isolated from an environmental system. It is shown that the interaction between the two qubits significantly affects the relaxation process. The synthetic effect of the interaction between the qubit-qubit interaction and qubit-reservoir interaction induces the entanglement sudden-birth and the violation of the Bell inequality, even if there is no entanglement in an initial state of the two qubits.