Local U(2,2) Symmetry in Relativistic Quantum Mechanics
arXiv:hep-th/9703083 · doi:10.1063/1.532638
Abstract
Local gauge freedom in relativistic quantum mechanics is derived from a measurement principle for space and time. For the Dirac equation, one obtains local U(2,2) gauge transformations acting on the spinor index of the wave functions. This local U(2,2) symmetry allows a unified description of electrodynamics and general relativity as a classical gauge theory.
18 pages, LaTeX, typo in second formula on page 6 corrected (published version)