Microscopic origin of black hole entropy from tachyon condensation

TL;DR

This paper proposes that black hole entropy can be understood through tachyon condensation processes near the horizon, linking particle decay into closed strings with entropy increase.

Contribution

It introduces a novel connection between tachyon effective actions and black hole entropy, suggesting decay into closed strings accounts for the entropy.

Findings

Hagedorn temperature equals Hawking temperature near the horizon

Particle decay into closed strings explains entropy increase

Area-entropy relation matches with closed string emission obeying the first law

Abstract

We show generically that the dynamics of a probe particle near the event horizon of a non-extreme black hole is described by the tachyon effective action. The Hagedorn temperature in the action is always equal to the Hawking temperature of the background black hole. The fact suggests that the infalling particle should decay completely into gravitons or closed strings approaching the event horizon. The increased area in the black hole due to absorption of a particle should be interpreted as the entropy of degenerate states of the closed strings that the particle decays into. With the energy match condition between the infalling particle and the emitted closed strings on the event horizon, we examine this variational area-entropy relation and find that it matches in all cases if the closed string emission process from an unstable D0-brane obeys the first law.