S. Hollands

We derive hamiltionian generators of asymptotic symmetries for general relativity with asymptotic AdS boundary conditions using the ``covariant phase space'' method of Wald et al. We then compare our results with other definitions that have been proposed in the literature. We find that our definition agrees with that proposed by Ashtekar et al, with the spinor definition, and with the background dependent definition of Henneaux and Teitelboim. Our definition disagrees with the one obtained from the ``counterterm subtraction method,'' but the difference is found to consist only of a ``constant offset'' that is determined entirely in terms of the boundary metric. We finally discuss and justify our boundary conditions by a linear perturbation analysis, and we comment on generalizations of our boundary conditions, as well as inclusion of matter fields.

We further explore the counter-term subtraction definition of charges (e.g., energy) for classical gravitating theories in spacetimes of relevance to gauge/gravity dualities; i.e., in asymptotically anti-de Sitter spaces and their kin. In particular, we show in general that charges defined via the counter-term subtraction method generate the desired asymptotic symmetries. As a result, they can differ from any other such charges, such as those defined by bulk spacetime-covariant techniques, only by a function of auxiliary non-dynamical structures such as a choice of conformal frame at infinity (i.e., a function of the boundary fields alone). Our argument is based on the Peierls bracket, and in the AdS context allows us to demonstrate the above result even for asymptotic symmetries which generate only conformal symmetries of the boundary (in the chosen conformal frame). We also generalize the counter-term subtraction construction of charges to the case in which additional non-vanishing boundary fields are present.