This simulation tests a cosmological conjecture: that matter and antimatter carry opposite gravitational charges. Under this modified gravity, matter attracts matter and antimatter attracts antimatter — but matter and antimatter repel each other.
Starting from a random mixed distribution, the repulsion between opposite-charge particles drives natural domain separation. Annihilation events occur only at the shrinking boundaries between domains, leaving a small residue that the conjecture predicts should approach roughly one-in-a-billion at cosmological scales.
The entire physics modification is a single sign change: F = G·m₁·m₂·q₁·q₂ / r²
where q = +1 for matter and −1 for antimatter.