Recovery of the nonlinearity from the modified scattering map

Abstract: We consider a class of one-dimensional nonlinear Schr\"odinger equations of the form [ (i\partial_t+\Delta)u = [1+a]|u|^2 u. ] For suitable localized functions $a$, such equations admit a small-data modified scattering theory, which incorporates the standard logarithmic phase correction. In this work, we prove that the small-data modified scattering behavior uniquely determines the inhomogeneity $a$.