Equality of the Hilbert Hamiltonian and the canonical Hamiltonian for gauge theories in a static spacetime
arXiv:2305.06209 · doi:10.1103/PhysRevD.107.125021
Abstract
The Hilbert energy-momentum tensor for gauge-fixed non-Abelian gauge theories, defined by the variational derivative of the action with respect to the space-time metric, is a tensor under general coordinate transformations, symmetric in its indices, and BRST invariant. The canonical energy-momentum tensor has none of these properties but the canonical Hamiltonian does correctly generate the time dependence of the fields. It is shown that the Hilbert Hamiltonian is equal to the canonical Hamiltonian for a general gauge theory coupled to spin 1/2 and spin 0 matter fields (including an term) in a static background metric ( and ). The equality depends on on the Gauss's law constraint but not on the dynamical Euler-Lagrange equations.