Manifestations of quantum gravity in scalar QED phenomena.

Quantum gravitational corrections to the effective potential, at one-loop level and in the leading-log approximation, for scalar quantum electrodynamics with higher-derivative gravity —which is taken as an effective theory for quantum gravity (QG)— are calculated. We point out the appearence of relevant phenomena caused by quantum gravity, like dimensional transmutation, QG-driven instabilities of the potential, QG corrrections to scalar-to-vector mass ratios, and curvature-induced phase transitions, whose existence is shown by means of analytical and numerical study. PACS 04.60.+n, 11.15.Ex, 12.10.Gq, 12.20.-m, 12.25+e E-mail: [email protected]. Address june-september 1994: Department of Physics, Faculty of Sciences, Hiroshima University, Higashi-Hiroshima 724, Japan. E-mail: [email protected]. On leave of absence from Tomsk Pedagogical Institute, 634041 Tomsk, Russian Federation. E-mail: [email protected]