Physics Cosmic Scale

The existence of all matter in the universe might be the result of tiny black holes exploding shortly after the Big Bang.

April 1, 2026

Original Paper

Baryogenesis from Exploding Primordial Black Holes

Alexandra P. Klipfel, Miguel Vanvlasselaer, Sokratis Trifinopoulos, David I. Kaiser

arXiv · 2603.29024

The Takeaway

Physics struggles to explain why the universe is full of matter instead of being empty. This paper suggests that microscopic black holes evaporating in the early universe created 'bubbles' of superheated fluid that acted as factories for creating the atoms that eventually formed stars and people.

From the abstract

Exploding primordial black holes can source baryon asymmetry soon after the electroweak phase transition, as high-energy Hawking radiation drives ultrarelativistic shocks in the surrounding plasma. The shocks and their trailing rarefaction waves delineate two bubble-like walls around a shell of superheated fluid, in which electroweak symmetry is restored. These moving interfaces source chiral charge, which is converted to baryon number. Upon adding a simple CP-violating operator at the TeV scale