ACTION AND HAMILTONIAN FOR ETERNAL BLACK-HOLES

We present the Hamiltonian, quasilocal energy, and angular momentum fo r a spacetime region spatially bounded by two timelike surfaces. The r esults are applied to the particular case of a spacetime representing an eternal black hole. It is shown that in the case when the boundarie s are located in two different wedges of the Kruskal diagram, the Hami ltonian is of the form H = H-+ - H--, where H-+ and H-- are the Hamilt onian functions for the right and left wedges, respectively. The obtai ned results strongly suggest a generalization beyond small perturbatio ns of a thermofield dynamics description of quantum effects in black h oles.