Phase transition at λ_c ≈ 3.298: active ↔ absorbing state
Contact process: active site at rate μ becomes inactive; each active site infects each neighbor at rate λ/2.
Critical point λ_c/μ ≈ 3.298 in 1+1D. Universality class: Directed Percolation.
Critical exponents: β≈0.276, ν_⊥≈1.097, ν_∥≈1.734, δ≈0.159.