Hawking radiation via tachyon condensation and its implications to tachyon cosmology

Hawking radiation can be derived from the collapsing process of matter to form a black hole. In this work, we show in more detail that the freely infalling process of a probe (D-)particle (or point-like object) in a non-extreme black hole background is essentially a tachyon condensation process. That is, a probe D-particle will behave as an unstable D-particle in the near-horizon region of a non-extreme black hole. From this point of view, Hawking radiation can be viewed as the thermal radiation from rolling tachyon on an unstable D-particle (i.e., the infalling probe) at the Hagedorn temperature. The result has interesting implications to tachyon cosmology: the uniform tachyon rolling in cosmology can automatically create particle pairs at late times, via a mechanism just like the Hawking radiation process near a black hole. So this particle creation process can naturally give rise to a hot universe with thermal perturbations beyond tachyon inflation, providing an alternative reheating mechanism.Comment: 22 page