Black hole gas in TeV-gravity models

In a plasma at temperature close to the fundamental scale a small fraction of particles will experience transplanckian collisions that may result in microscopic black holes (BHs). We study the dynamics of a system (a black hole gas) defined by radiation at a given temperature coupled to a distribution of BHs of different mass. Our analysis includes the production of BHs in photon-photon collisions, BH evaporation, the absorption of radiation, collisions of two BHs to give a larger one, and the effects of the expansion. We find that the system may follow two different generic paths depending on the initial temperature of the plasma.