Critical slowing down defeated by cluster flips near T_c ≈ 2.269
Magnetization |m|—
Energy/site—
Cluster size—
Susceptibility χ—
T_c (exact)2.2692
Wolff algorithm builds clusters with probability p = 1 − e^(−2J/kT) along like-spin bonds, flips entire cluster. Eliminates critical slowing down (z ≈ 0 vs Metropolis z ≈ 2). Red = spin up, blue = spin down. Susceptibility peaks at T_c.