False Vacuum Lumps with the Fermionic Core

Stable gravitating lumps with a false vacuum core surrounded by the true vacuum in a scalar field potential exist in the presence of fermions at the core. These objects may exist in the universe at various scales.Comment: 3 pages, 4 figures. To appear in the proceedings of the Tenth Marcel Grossmann Meeting on General Relativit

Gravitating Fermionic Lumps with a False Vacuum Core

We investigate gravitating lumps with a false vacuum core surrounded by the true vacuum in a scalar field potential. Such configurations become possible in the Einstein gravity in the presence of fermions at the core. Gravitational interactions as well as Yukawa interactions are essential for such lumps to exist. The mass and size of gravitating lumps sensitively depend on the scale characterizing the scalar field potential and the density of fermions. These objects can exist in the universe at various scales.Comment: 17 pages, 16 figures. Final published versio

Antimatter from Microscopic Black Holes

The spectrum of positrons and antiprotons produced by the outflow of high temperature matter surrounding microscopic black holes is calculated for energies between five GeV and the Planck energy. The results may be applicable for the last few hours and minutes of a microscopic black hole's lifetime.Comment: 7 pages, 3 figure