WHITE HOLES, BLACK-HOLES, AND CPT IN 2 DIMENSIONS

It is argued that a unitarity-violating but weakly CPT invariant super scattering matrix exists for leading-order large-N dilaton gravity, if and only if one includes in the Hilbert space Planckian ''thunderpop' ' excitations which create white holes. CPT apparently cannot be reali zed in a low-energy effective theory in which such states have been in tegrated out. Rules for computing leading-large-N superscattering are described in terms of quantum field theory on a single multiply connec ted spacetime obtained by sewing the future (past) horizons of the ori ginal spacetime with the past (future) horizons of its CPT conjugate. Some difficulties which may arise in going beyond leading order in 1/N are briefly discussed.