On the Singularities in the Susceptibility Expansion for the Two-Dimensional Ising Model
arXiv:1403.3966 · doi:10.1007/s10955-014-1061-4
Abstract
For temperatures below the critical temperature, the magnetic susceptibility for the two-dimensional isotropic Ising model can be expressed in terms of an infinite series of multiple integrals. With respect to a parameter related to temperature and the interaction constant, the integrals may be extended to functions analytic outside the unit circle. In a groundbreaking paper, B. G. Nickel identified a class of singularities of these integrals on the unit circle. In this note we show that there are no other singularities on the unit circle.
13 pages