Tetrapartite entanglement measures of W-class in noninertial frames
Torres-Arenas Ariadna J1, López-Zúñiga Edgar O1, 2, Antonio Saldaña-Herrera J1, 2, Dong Qian1, Sun Guo-Hua3, Dong Shi-Hai1, †
       

Entanglement measure (1–1 tangle) as a function of rc=rd.