Phenomenology of space-time imperfection. I. Nonlocal defects

If space-time is emergent from a fundamentally nongeometric theory it will generically be left with defects. Such defects need not respect the locality that emerges with the background. Here, we develop a phenomenological model that parametrizes the effects of nonlocal defects on the propagation of particles. In this model, Lorentz invariance is preserved on the average. We derive constraints on the density of defects from various experiments.