K (coupling): —
K' (renormalized): —
RG steps: 0
Free energy: —
About: The 1D Ising model's coupling constant K = J/kT flows under real-space RG via the exact recursion K' = ½ ln(cosh 2K). This always flows to K=0 (high-temperature fixed point), reflecting that the 1D model has no phase transition. The flow diagram shows K on the horizontal axis; the diagonal is K'=K. The top panel shows block-spin coarse-graining visually.