The time dependence of API for different number of BEC atoms with γ₁ = γ₂ = 0.01 G, g₁ = g₂ = 0.5 G in terms of the dimensionless time τ = gt in the resonance regime. (a) N = 10, (b) N = 20, (c) N = 50, (d) N = 100.