  We study the O(2N) model at criticality in three dimensions in the double
scaling limit of large N and large charge. We show that the large-charge
expansion is an asymptotic series, and we use resurgence techniques to study
the non-perturbative corrections and to extend the validity of the effective
field theory to any value of the charge. We conjecture the general form of the
non-perturbative behavior of the conformal dimensions for any value of N and
find very good agreement with previous lattice data.
