Free-fall non-universality in quantum theory
We show by embodying the Einstein equivalence principle - local Poincar\'{e} invariance - and general covariance in quantum theory that wave-function spreading rules out the universality of free fall, i.e. the free-fall trajectory of a quantum (test) particle depends on its internal properties. We provide a quantitative estimate of the free-fall non-universality in terms of the E\"{o}tv\"{o}s parameter, which turns out to be measurable in atom interferometry.