The influence of the non-Markovian effect on the dynamics of atomic squeezing factor F₂ (black solid line) and the concurrence C (blue dashed line) versus γ₀t when Ω = γ₀. (a) λ = 5γ₀; (b) λ = 0.5γ₀; (c) λ = 0.05γ₀. Other parameters are θ = π/4, φ = 0, and ω₀ = 20γ₀. The red dotted lines indicate the envelope lines of the F₂-oscillations.