A new attempt towards the unification of space-time and internal gauge symmetries
arXiv:math-ph/0610005 · doi:10.1088/0305-4470/39/7/016
Abstract
The neat formulation that describes the gauge interactions associated with internal symmetries is extended to the case of a simple, yet non-trivial, symmetry group structure which mixes gravity and electromagnetism by associating a gauge symmetry with a central extension of the Poincaré group.
20 pages