Lectures On Black Hole Evaporation and Information Loss

TL;DR

This paper discusses a scenario where black hole remnants, called cornucopions, allow information loss during evaporation without violating quantum mechanics, and explores their compatibility with string theory models of black hole entropy.

Contribution

It introduces the cornucopion remnant scenario as a novel endpoint for black hole evaporation and argues for its consistency with string theory models of entropy.

Findings

Information can be lost without violating quantum mechanics.

Black hole remnants can be large and connected to our universe.

The scenario is potentially testable experimentally.

Abstract

Trieste Spring School Lectures describing the author's opinions about black hole evaporation and information loss. The remnant, or cornucopion scenario for the endpoint of Hawking evaporation is described in detail. In this picture information can be lost to the original asymptotic observer without violating the rules of quantum mechanics, because a black hole remnant is viewed as a large space connected onto our own by an almost pointlike opening. It does not behave like an elementary particle. Objections to remnants are refuted and the (remote) possibility of testing this scenario experimentally is discussed. Also included is a brief description of Susskind's picture of the stringy origin of Bekenstein-Hawking entropy. An attempt is made to argue that the cornucopion picture and Susskind's model of the states responsible for black hole entropy are compatible with each other. Information is lost to the asymptotic observer in Hawking evaporation, but the information encoded in the BH entropy remains in causal contact with him and is re-emitted with the Hawking radiation.