Brane Symmetries Revisited: Symmetries of Tensile and Tensionless Branes in Possibly Degenerate Metrics and their Manifestations
Leron Borsten, Mateo Galdeano, Hyungrok Kim
TL;DR
The paper classifies classical and bulk symmetries of bosonic branes (tensile and tensionless) moving in target spaces with potentially degenerate metrics. Using gauge-fixed p-brane actions, the Polyakov framework, and generalized geometry, it identifies when Killing and conformal Killing tensors generate worldvolume symmetries and how these extend in tensionless and degenerate cases. It demonstrates that, beyond standard Killing-vector symmetries, tensionless limits and degenerate target metrics yield enhanced or novel symmetries, and connects these to a Duff–Lu generalized metric that makes T- and U-dualities explicit, as well as to worldvolume Noether charges and prospective W-algebras. The work also discusses how brane symmetries reflect and constrain bulk theories, including bulk scalar field theories and string/M-theory contexts, with implications for no-global-symmetries principles in quantum gravity and for generalized geometric formulations of brane dynamics.
Abstract
We analyse the symmetries of tensionless and tensile branes moving in a target space with a possibly degenerate metric, with the worldvolume metric remaining nondegenerate. We recover known results about symmetries of strings and branes as well as new results in the tensionless and degenerate-metric cases. We comment on ramifications in the corresponding bulk theories.