Non-Markovianity of a qubit coupled with an isotropic Lipkin–Meshkov–Glick bath
Tian Li-Jun, Ti Min-Min, Zhai Xiang-Dong
       
The curves of h ( t ) versus t with different λ′ are plotted in (a) λ′ = 0.1, (b) λ′ = 0.2, (c) λ′ = 0.3, (d) λ′ = 0.4 in the case of N = 500, λ = 1.1.