Abstract
The high-temperature expansions of the partition function and susceptibility of the Ising model and the number of self-avoiding walks and polygons are obtained exactly up to the eleventh order (in "bonds" or "steps") for the general -dimensional simple hypercubical lattices. Exact expansions of and in power of where , and where , for are derived up to the fifth order. The zero-order terms are the Bragg-Williams and Bethe approximations, respectively. The Ising critical point is found to have the expansion while for self-avoiding walks
Numerical extrapolation yields accurate estimates for and when and indicates that diverges as where and that with
- Received 17 July 1963
DOI:https://doi.org/10.1103/PhysRev.133.A224
©1964 American Physical Society