Ising Renormalization Group

Block-spin coarse-graining flows coupling constant toward fixed points

Temperature K = J/kT: 0.44 Block-spin Step Auto Run Reset

RG Flow: Each step coarse-grains 2×2 blocks to single spins by majority vote. The effective coupling K flows under this map. Below the critical point K_c≈0.441 it flows to K=0 (disordered fixed point); above it flows to K=∞ (ordered fixed point). The critical point is an unstable fixed point — the phase transition.