Quantum Gravity: General Introduction and Recent Developments

Abstract

I briefly review the current status of quantum gravity. After giving some general motivations for the need of such a theory, I discuss the main approaches in quantizing general relativity: Covariant approaches (perturbation theory, effective theory, and path integrals) and canonical approaches (quantum geometrodynamics, loop quantum gravity). I then address quantum gravitational aspects of string theory. This is followed by a discussion of black holes and quantum cosmology. I end with some remarks on the observational status of quantum gravity.Comment: 21 pages, 6 figures, invited contribution for "Annalen der Physik", v2: minor corrections, additional reference