Quasilocal formalism and thermodynamics of asymptotically flat black objects

Abstract

We study the properties of 5-dimensional black objects by using the renormalized boundary stress-tensor for locally asymptotically flat spacetimes. This provides a more refined form of the quasilocal formalism which is useful for a holographic interpretation of asymptotically flat gravity. We apply this technique to examine the thermodynamic properties of black holes, black rings, and black strings. The advantage of using this method is that we can go beyond the `thin ring' approximation and compute the boundary stress tensor for any general (thin or fat) black ring solution. We argue that the boundary stress tensor encodes the necessarily information to distinguish between black objects with different horizon topologies in the bulk. We also study in detail the susy black ring and clarify the relation between the asymptotic charges and the charges defined at the horizon. Furthermore, we obtain the balance condition for `thin' dipole black rings.