Contact Process — Directed Percolation

The 1D contact process is the canonical model for absorbing-state phase transitions in the directed percolation universality class. Sites can be active (infected) or inactive. Active sites infect neighbors at rate λ and recover at rate 1. Below the critical threshold λ_c ≈ 3.298, activity dies out; above it, activity persists. The space-time diagram reveals the fractal critical point.

Active: — | Density: —