Building block approach to asymptotic symmetries in general relativity

Asymptotic symmetries of black hole spacetimes have received much attention as a possible origin of the Bekenstein-Hawking entropy in black hole thermodynamics. In general, it takes heavy efforts to find appropriate asymptotic conditions on a metric and a Lie algebra generating the transformation of symmetries with which the corresponding charges are integrable. We here propose a powerful approach to construct building blocks of asymptotic symmetries of a given spacetime metric. Our algorithmic approach makes it easier to explore asymptotic symmetries in any spacetime than in conventional approaches. As an explicit application, we analyze the asymptotic symmetries on Rindler horizon. We find a new class of symmetries related with dilatation transformations perpendicular to the horizon, which we term superdilatations.