Negativities of bipartition q 1 | Q n − 1 , as a function of p d , for the states | Ψ n 〉 (solid lines or dashed dot dot lines) and | Φ n 〉 (dashed lines) with θ = π / 4 under the local dephasing. The systems with n = 2 , 3 , … , 7 are shown with gray, pink, blue, green, orange, black curves, respectively.