Evolution of near extremal black holes

TL;DR

This paper calculates emission rates of near extremal black holes, revealing how they evolve towards charge equality and discussing implications for black hole information loss and D-brane models.

Contribution

It provides the first detailed calculation of greybody factors and emission rate ratios for near extremal Reissner-Nordstrom black holes in four and five dimensions.

Findings

Evolution favors equal charge states.

Neutral emission dominates decay to extremality.

Results support black hole and D-brane emission rate agreement.

Abstract

Near extreme black holes can lose their charge and decay by the emission of massive BPS charged particles. We calculate the greybody factors for low energy charged and neutral scalar emission from four and five dimensional near extremal Reissner-Nordstrom black holes. We use the corresponding emission rates to obtain ratios of the rates of loss of excess energy by charged and neutral emission, which are moduli independent, depending only on the integral charges and the horizon potentials. We consider scattering experiments, finding that evolution towards a state in which the integral charges are equal is favoured, but neutral emission will dominate the decay back to extremality except when one charge is much greater than the others. The implications of our results for the agreement between black hole and D-brane emission rates and for the information loss puzzle are then discussed.