The unitarity crisis, nonviolent unitarization, and implications for quantum spacetime

TL;DR

This paper discusses the unitarity crisis in black hole physics, proposing nonviolent unitarization as a resolution, which involves new horizon-scale interactions with potential observable effects and implications for quantum spacetime.

Contribution

It introduces nonviolent unitarization as a novel approach to resolve the unitarity crisis, emphasizing horizon-scale interactions and their implications for quantum spacetime.

Findings

Proposes horizon-scale interactions as a resolution to the unitarity crisis.

Suggests potential observable effects in gravitational waves and electromagnetic signals.

Discusses implications for fundamental quantum spacetime theories.

Abstract

This contribution overviews the information paradox, or perhaps more aptly "unitarity crisis," and a proposed resolution called nonviolent unitarization. It begins by examining the conflict of principles that yields the crisis, which can be phrased in terms of a "black hole theorem" summarizing how basic assumptions come into conflict. Proposed resolutions of the conflict, along with problems with them, are overviewed. The very important underlying question of localization of information and its role is discussed at some length, taking into account effects of perturbative gravity. The difficulty in finding a consistent scenario for black hole evolution strongly suggests new interactions on event horizon scales; a "minimal" set of assumptions about these are parameterized in nonviolent unitarization. Possible criticisms of this scenario, and some responses, are given. New interactions at event horizon scales potentially lead to observable effects, via gravitational wave or electromagnetic channels, which are briefly discussed. A possible origin of nonviolent unitarization effects from a more fundamental description of quantum spacetime, and possible implications for such a description, are also briefly discussed.