UC Santa Barbara

In the semiclassical approximation, quantum field theory suggests that black

holes eventually evaporate in a manner largely independent of their internal structure. Doing so, however, leads to a violation of unitarity of quantum mechanics, rendering the system inconsistent. One possible resolution is soft violations of locality in the near horizon region. The first consistency check is whether such a proposal can actually get the information out. Using quantum information techniques, a large class of evolutions into paired states is ruled out. More generally, information transfer can be characterized by the mutual information of a specially prepared state. Minimizing this quantity saturates a subadditivity inequality, leading to "subspace transfer"; maximizing it generically leads to an enhanced particle flux. Using the tools of effective field theory, one can then try to model the nonlocality as arising from an effective source localized near the horizon. To get information out at the right rate, this source must have a characteristic size. The horizon is altered, but nonviolent. This model also naturally accommodates black hole mining, avoiding a potential flaw. Having passed important consistency checks, nonviolent nonlocality is a viable solution to the information paradox.