Influence of dipole-dipole interaction on dynamics of entangled Greenberger–Horne–Zeilinger states for two qubits

The influence of dipole-dipole interaction on dynamics of three- and four-particle GHZ states for two $\Delta$-type superconducting flux cubits interacting with one or two different electronic $LC$ cavities via two-photon processes has been investigated. The results show that dipole-dipole interaction does not lead to the disappearance of the effect of entanglement sudden death and does not change the maximum degree of entanglement.