Fig. 1. Schematic of microcavity coupling with atom

Fig. 2. Quantum coherence as a function of R when effective magnetic field is at critical point (λ=1)

Fig. 3. Three-dimensional graph of quantum coherence and its quantum critical phenomena. (a) Relationship among quantum coherence, anisotropic parameters γ, and magnetic field strength λ; (b) curves of first derivative of quantum coherence with respect to effective magnetic field (R=5)

Fig. 4. Evolution of effective magnetic quantum coherence with time (Γ_i=0.3,λ=1,n-i=0)