Continuum Limit of Susceptibility from Strong Coupling Expansion

On the basis of a strong-coupling expansion, we reinvestigate the scaling behavior of the susceptibility chi of the two-dimensional O(N) sigma model on the square lattice with Pad,-Borel approximants. To exploit the Borel transform, we express the bare coupling g in a series expansion in chi. For large N, the Pad,-Borel approximants exhibit scaling behavior at the four-loop level. We estimate the nonperturbative constant associated with the susceptibility for N a parts per thousand yenaEuro parts per thousand 3 and compare the results with previous analytica l results and Monte Carlo data.