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".
[1] Fermi balls can be modeled as a type of non-topological soliton.
[2] This mechanism is initiated after the Yukawa potential begins to play a role after the Fermi balls become unstable.
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.