The goal of the article is to provide some glimpses into the challenges and successes of quantum gravity. After a general introduction, for concreteness I focus on a specific approach which goes under the name loop quantum gravity. The underlying ideas are first summarized and recent advances are then illustrated by applying these ideas to cosmology. Quantum effects of geometry resolve the big-bang singularity of classical general relativity. Quantum physics does not break down at the big-bang. In simple models where details have been fully worked out, there is a pre-big-bang branch joined to the current post-big-bang branch by well-defined quantum evolution.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)