BLACK-HOLE COMPLEMENTARITY VERSUS LOCALITY

The evaporation of a large mass black hole can be described throughout most of its lifetime by a low-energy effective theory defined on a su itably chosen set of smooth spacelike hypersurfaces. The conventional argument for information loss rests on the assumption that the effecti ve theory is a local quantum field theory. We present evidence that th is assumption fails in the context of string theory. The commutator of operators in light-front string theory, corresponding to certain low- energy observers on opposite sides of the event horizon, remains large even when these observers are spacelike separated by a macroscopic di stance. This suggests that degrees of freedom inside a black hole shou ld not be viewed as independent from those outside the event horizon. These nonlocal effects are only significant under extreme kinematic ci rcumstances, such as in the high-redshift geometry of a black hole. Co mmutators of spacelike separated operators corresponding to ordinary l ow-energy observers in Minkowski space are strongly suppressed in stri ng theory.