Information-theoretic arguments are used to obtain a link between the
accurate linearity of Schrodinger's equation and Lorentz invariance: A possible
violation of the latter at short distances would imply the appearance of
nonlinear corrections to quantum theory. Nonlinear corrections can also appear
in a Lorentz invariant theory in the form of higher derivative terms that are
determined by a length scale, possibly the Planck length. It is suggested that
the best place to look for evidence of such quantum nonlinear effects is in
neutrino physics and cosmology.Comment: 3 pages; Presented at the DICE 2004 workshop; Sept 2004, Piombino
Italy. Minor corrections: this is the proceedings Versio