Epidemic spreading on a lattice — absorbing state phase transition
Density: 0.000 | Time: 0
The contact process is a stochastic model of epidemic spreading where infected sites (bright) infect neighbors at rate λ and recover at rate μ. Near the critical ratio λ/μ ≈ 1.65 (DP universality class), the system exhibits a continuous absorbing-state phase transition. The space-time diagram (time flows downward) reveals directed percolation clusters with fractal boundaries.