Exploring Global Symmetries in Linearized Gravity

Recent research by Chris Hull, Maxwell L. Hutt, and Ulf Lindström, titled "Generalised symmetries in linear gravity" (arXiv:2409.00178), explores the global symmetries present in linearized gravity. The authors identify a global symmetry under which the graviton can be shifted by a symmetric tensor that meets a specific flatness condition. Additionally, they describe a dual symmetry linked to a global shift symmetry of the dual graviton theory.

The study reveals that the conserved charges associated with these symmetries conform to a centrally-extended algebra. The authors discuss the gauging of these global symmetries and identify an obstruction to the simultaneous gauging of both symmetries, interpreting this as a mixed 't Hooft anomaly for the ungauged theory.

The implications of these findings are significant, drawing parallels to similar structures observed in Maxwell theory. The authors interpret the graviton and dual graviton as Nambu-Goldstone modes for the identified shift symmetries. This research could enhance the understanding of gravitational theories and their underlying symmetries, potentially influencing future developments in theoretical physics and cosmology.