Primordial black holes from scalar field evolution in the early universe
  Scalar condensates with large expectation values can form in the early
universe, for example, in theories with supersymmetry. The condensate can
undergo fragmentation into Q-balls before decaying. If the Q-balls dominate the
energy density for some period of time, statistical fluctuations in their
number density can lead to formation of primordial black holes (PBH). In the
case of supersymmetry the mass range is limited from above by $10^{23}$g. For a
general charged scalar field, this robust mechanism can generate black holes
over a much broader mass range, including the black holes with masses of 1-100
solar masses, which is relevant for LIGO observations of gravitational waves.
Topological defects can lead to formation of PBH in a similar fashion.
