Isolated horizons, $p$-form matter fields, topology, and the black-hole/string correspondence principle

We study the mechanics of $D$-dimensional isolated horizons (IHs) for Einstein gravity in the presence of arbitrary $p$-form matter fields. This generalizes the analysis of Copsey and Horowitz to nonstationary spacetimes and therefore the local first law in $D>4$ dimensions to include nonmonopolar (dipole) charges. The only requirement for the local first law to hold is that the action has to be differentiable. The resulting conserved charges are all intrinsic to the horizon and are independent of the topology of the horizon cross sections. We explicitly calculate the local charges for five-dimensional black holes and black rings that are relevant within the context of superstring theory. We conclude with some comments on the black-hole/string correspondence principle and argue that IHs (or some other quasilocal variant) should play a fundamental role in superstring theory.