Continuum limit of susceptibility from strong coupling expansion: Two   dimensional non-linear O(N) sigma model at N>= 3
  Based on the strong coupling expansion, we reinvestigate the scaling behavior of the susceptibility chi of two-dimensional O(N) sigma model on the square lattice by the use of Pade-Borel approximants. To exploit the Borel transform, we express the bare coupling g in series expansion in chi. At large N, Pade-Borel approximants exhibit the scaling behavior at the four-loop level. Then, the estimation of the non-perturbative constant associated with the susceptibility is performed for N>=3 and the results are compared with the available theoretical results and Monte Carlo data. 
Hirofumi Yamada
hep-lat cond-mat.stat-mech hep-th