HORNED PARTICLES AS THE END-POINT OF HAWKING EVAPORATION

This essay reviews recent developments in the theory of Hawking evaporation of black holes. Study of near extremal magnetically charged black holes using a two plus four dimensional effective field theory has led to the concept of homed particles or cornucopion as the endpoint of Hawking evaporation. Horned particles are geometries containing two large asymptotic regions connected by microscopic necks. They look like point particles to an observer in any given asymptotic region, but in many ways behave like macroscopic objects. In particular, it is very difficult to pair produce them in external fields and their contribution to virtual loops is highly suppressed. They can serve as the remnants necessary to account for the information apparently lost in Hawking evaporation. The information simply goes into the new asymptotic region formed when the black hole collapses and evaporates.