Kavli Affiliate: Robert Wald | First 5 Authors: Robert M. Wald, , , , | Summary: We consider a general, classical theory of gravity in $n$ dimensions, arising from a diffeomorphism invariant Lagrangian. In any such theory, to each vector field, $ξ^a$, on spacetime one can associate a local symmetry and, hence, a Noether current […]

Kavli Affiliate: Robert Wald | First 5 Authors: Robert M. Wald, , , , | Summary: A simple proof of a strengthened form of the first law of black hole mechanics is presented. The proof is based directly upon the Hamiltonian formulation of general relativity, and it shows that the the first law variational formula […]