  The asymptotic kinematic limits of S-matrices are dominated by large
logarithms which, roughly speaking, fall into two categories: those which are
controlled by a renormalization group (RG) scale, which we may think of as logs
involving ratios of invariant mass scales, and those which are functions of
ratios of rapidities, so called "rapidity logs". It has been pointed out by
Caron-Huot and Wilhlem [1] that RG anomalous dimension can be extracted from
the phase of the S-matrix, which can greatly simplify calculations via
unitarity methods. In this paper we generalize the results of [1] to show that
the phase can be used to reconstruct rapidity anomalous dimensions, by
performing a complex boost. The methodology introduced here also allows one to
calculate without the need for a rapidity regulator. We demonstrate the use of
this method to derive the rapidity anomalous dimensions in the Sudakov form
factor, the two parton soft function and the Regge trajectory in QCD.
