Right after the Big Bang, the Universe resembled a bubbling soup: pairs of particles and antiparticles would pop out of the vacuum and sink back in. But a sharp expansion — the era described by Alan Guth and Andrei Linde — slammed the lid on this pot. Random ripples froze in place, and particles outnumbered their antipodeans.
During their decay, these 'guests' gave rise to protons and electrons, and their movement stirred up electric currents — and the first magnetic fields. A similar scenario could have created an excess of dark matter — the invisible scaffolding that holds galaxies together.
Calculations yield the share of excess matter relative to entropy (a measure of chaos) and the strength of primordial magnetism, perfectly matching observations. Our entire world hinges on a minuscule imbalance: one extra particle for every billion photons — and that was enough for stars, planets, life. Everything was born from a tremor in curved spacetime.
as written by the authors arXiv:2603.27257
During the reheating epoch, gravitationally produced superheavy particle-antiparticle pairs undergo quantum oscillations. Perturbations in their relative densities cross out the horizon, leading to an asymmetry of particles and antiparticles inside the horizon. Massive particles decay into light baryons and leptons, thereby explaining baryogenesis and leptogenesis, whose charged components must generate a nontrivial electric current, thereby producing a primordial magnetic field (magnetogenesis). As a result, the baryon (lepton) number-to-entropy ratio and the primordial magnetic field bound are consistent with observational data. We also discuss darkogenesis, the origin of dark matter and anti-dark matter asymmetry.
The imbalance between matter and antimatter was minuscule: just one extra particle per billion photons. But without it, galaxies, stars, and life would never have emerged.