Symmetries and strings in field theory and gravity

We discuss aspects of global and gauged symmetries in quantum field theory and quantum gravity, focusing on discrete gauge symmetries. An effective Lagrangian description of ${\mathbb{Z}}_{p}$ gauge theories shows that they are associated with an emergent ${\mathbb{Z}}_{p}$ 1-form (Kalb-Ramond) gauge symmetry. This understanding leads us to uncover new observables and new phenomena in nonlinear $\ensuremath{\sigma}$ models. It also allows us to expand on Polchinski's classification of cosmic strings. We argue that in models of quantum gravity, there are no global symmetries, all continuous gauge symmetries are compact, and all charges allowed by Dirac quantization are present in the spectrum. These conjectures…

• UD
  U.S. Department of Energy