Calculating the ground state entanglement of a two-dimensional spin star lattice

In this study, the ground states of a 6-qubit star lattice are studied in the presence of a magnetic field. In addition, their bipartite and multipartite entanglements are obtained, using concurrence as a measure of bipartite entanglement and Meyer–Wallach measure and its generalizations as the measures of multipartite entanglement. Also a comprehensive structure of their entanglement is presented and described. It is shown that the external magnetic field is a tuning agent that determines the separable ground states, the global entangled states and the states between them. Determination of these states helps to choose the required ones, for different quantum information processes.