How compact macroscopic dark-matter objects called Fermi-balls arise in a realistic multi-particle dark matter model and how a first-order phase transition in the same model produces a detectable gravitational-wave signal. The inert scalar doublet (a standard WIMP setup that is under-abundant in its 'desert' region) is extended by a gauge-singlet fermion carrying a conserved global charge and a singlet scalar; the fermion replenishes the relic density, and its finite-temperature potential develops coexisting false and true vacua. Learners see the three conditions for Fermi-ball formation, how trapped fermions form solitonic dark matter contributing to the relic abundance, and how the bubble-nucleation phase transition sources a stochastic gravitational-wave spectrum observable at BBO and U-DECIGO.
Embeds Fermi-balls - compact macroscopic dark-matter objects formed when a charge-carrying fermion is trapped in the false vacuum of a first-order phase transition - into a UV-complete two-component …