HEP Theory Journal Club

Global symmetries & gravity: the QCD axion quality problem

Gonzalo Alonso-Alvarez

McGill

There exists evidence pointing towards quantum gravity being a source of breaking of continuous global symmetries. This expectation is mostly backed by arguments based on string theoretical constructions and semiclassical calculations. As an important phenomenological consequence, the viability of the Peccei-Quinn solution to the strong CP problem is threatened by these quantum gravitational effects. In this talk, I will review the situation of global symmetries and gravity, focusing on wormholes as a source of symmetry breaking and its implications for the QCD axion and other pseudo Nambu-Goldstone bosons