Fermi ball

In cosmology, Fermi balls are hypothetical objects that may have been created in the early history of the universe by spontaneous symmetry breaking. One paper has described them as "charged SLAC-bag type structures". Fermi balls can be modeled as a type of non-topological soliton.

The concept is named after Enrico Fermi (see Fermion).

Dark matter
A paper by theoretical physicists at Seoul National University has proposed that Fermi balls may be implicated in the formation of primordial black holes from a cosmic first-order phase transition, as a candidate explanation for dark matter.