Non-Markovianity of a qubit coupled with an isotropic Lipkin–Meshkov–Glick bath
Tian Li-Jun, Ti Min-Min, Zhai Xiang-Dong
       
The non-Markovianity versus λ′ with different values of N . N = 500 (solid line), N = 1000 (dashed line), N = 1500 (dotted line). (a) λ = 0.8. (b) λ′ = 0.5.