“On Information Loss in AdS_3/CFT_2”
A pure state in CFT with large conformal weight will behave like a thermal system in the limit of large central charge. In particular, in the semiclassical limit, it is well approximated by the BTZ black hole configuration. Associated with this classical BTZ black hole picture is the information loss problem, which manifests itself in the present context as i) the correlators in the BTZ background possess “forbidden singularities” in the Euclidean region, and ii) the correlators decay exponentially late time in the Lorenzian region. By studying these correlators using AdS/CFT, we argue that information in fact can be restored by non-perturbative effects at finite c. This resolution may have certain universal features that also apply in more general cases.