Probing Lorentz Violating (Stringy) Quantum Space-Time Foam

Abstract

Quantum Space Time may be characterized by a plethora of novel phenomena, such as Lorentz violations and non‐trivial refractive indices, stochastic metric fluctuation effects leading to decoherence of quantum matter and non‐commutativity of space‐time coordinates. In string theory, which is one of the major approaches to quantum gravity, such coordinate non‐commutativities arise naturally in many instances. In the talk I review one such instance, which arises in the modern context of D‐brane defects in the background space time, over which string matter propagates. This serves as a prototype of space‐time foam in this context. I chose this model, over many others, because it may actually have some unique features that can be falsified experimentally either by means of high‐energy astrophysical observations or in some particle‐interferometers, such as neutral meson factories. In particular, the model may explain the recent observations of the FERMI Gamma‐Ray Telescope on delayed emission of 30 GeV photons from a distant Gamma‐Ray‐Burst 090510, in agreement with previous observations from the MAGIC and HESS Telescopes, but can also lead to falsifiable predictions for quantum foam effects in forthcoming upgrades of certain “particle interferometers”, such as neutral meson factories.