Heterogeneous SIS Epidemic — Quenched Mean-Field

SIS model on a network with heterogeneous degree distribution. Quenched mean-field theory predicts threshold λ_c = ⟨k⟩/⟨k²⟩. Scale-free networks have λ_c→0, meaning any infection spreads.

Infection rate λ 0.15

Recovery rate μ 0.50

Degree exponent γ 2.5

Max degree k_max 50

λ_c = -

⟨k⟩ = -

⟨k²⟩ = -

Prevalence ρ* = -