Non-Critical Liouville String Escapes Constraints on Generic Models of Quantum Gravity

It has recently been pointed out that generic models of quantum gravity must contend with severe phenomenological constraints imposed by gravitational Čerenkov radiation, neutrino oscillations and the cosmic microwave background radiation. We show how the non-critical Liouvillestring model of quantum gravity we have proposed escapes these constraints. It gives energetic particles subluminal velocities, obviating the danger of gravitational Čerenkov radiation. The effect on neutrino propagation is naturally flavour-independent, obviating any impact on oscillation phenomenology. Deviations from the expected black-body spectrum and the effects of time delays and stochastic fluctuations in the propagation of cosmic microwave background photons are negligible, as are their effects on observable spectral lines from high-redshift astrophysical objects. CERN-TH/2001-226 August 2001 a Theoretical Physics Division, CERN, CH-1211 Geneva 23, Switzerland b Theoretical Physics Group, Department of Physics, King’s College London, Strand, London WC2R 2LS, U.K. c Department of Physics, Texas A & M University, College Station, TX 77843, USA; Astroparticle Physics Group, Houston Advanced Research Center (HARC), Mitchell Campus, Woodlands, TX 77381, USA; Chair of Theoretical Physics, Academy of Athens, Division of Natural Sciences, 28 Panepistimiou Avenue, Athens 10679, Greece.