1999/09/07 by Kouichi Okunishi, Tomotoshi Nishino · 1 citation
Physics and Astronomy · #Complex Network Analysis Techniques #Quantum many-body systems #Theoretical and Computational Physics #cond-mat.stat-mech
paper · pdf · doi:10.1143/ptp.103.541
published as Prog. Theor. Phys. 103, (2000) 541-548 · 7 pages, 4 figures, submitted to Prog. Theor. Phys
arxiv created 1999/09/07 · openalex publication_date 2000/03/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the Kramers-Wannier approximation for the three-dimensional (3D) Ising model. The variational state is represented by an effective 2D Ising model, which contains two variational parameters. We numerically calculate the variational partition function using the corner transfer matrix renormalization group (CTMRG) method, and find its maximum with respect to the variational parameters. The value of the calculated transition point, Kc = 0.2184, is only 1.5% less than the true Kc. This result is better than that obtained using the corner transfer tensor renormalization group (CTTRG) approach. The calculated phase transition is mean-field like.