The article revives Lord Kelvin’s 19th-century idea of atoms as knots in the aether, now applied to explain the universe’s missing antimatter. Japanese physicists, led by Muneto Nitta from Hiroshima University’s International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM²), along with Minoru Eto and Yu Hamada, propose that cosmic knots formed in the early universe, providing a mechanism for baryogenesis—the tiny excess of matter over antimatter that allowed the universe to exist.

The Big Bang should have produced equal matter and antimatter, annihilating into radiation, but observations show a matter-dominated universe with just one extra matter particle per billion pairs. The Standard Model fails to explain this discrepancy, falling short by many orders of magnitude. The researchers combine two Standard Model extensions: gauged Baryon Number Minus Lepton Number (B–L) symmetry, which explains neutrino masses and introduces heavy right-handed neutrinos, and Peccei–Quinn (PQ) symmetry, which solves the strong CP problem and proposes axions as dark matter candidates. Keeping PQ global preserves axion physics, while gauging B–L adds a force carrier enabling superconducting behavior for knot formation.

In the post-Big Bang cooling, symmetry breaking created cosmic strings: magnetic flux tubes from B–L and superfluid vortices from PQ. Their interaction via Chern–Simons coupling forms stable knot solitons—metastable, topologically locked configurations. These knots dominated a brief era, their energy density surpassing radiation, before quantum tunneling caused collapse, producing heavy right-handed neutrinos that decayed with a matter bias, generating the observed imbalance and reheating the universe to 100 GeV—the critical temperature for electroweak reactions.

Key findings include a realistic model where knots naturally yield the matter surplus, with calculations matching observations for 10¹² GeV neutrino masses. Implications extend to detectable gravitational waves: the knot era would produce a higher-frequency spectrum, probeable by future detectors like LISA, Cosmic Explorer, and DECIGO. This topological stability makes the result model-independent, offering a testable path for a longstanding mystery.

Expert quotes highlight the significance: Nitta states, “This study addresses one of the most fundamental mysteries in physics: why our Universe is made of matter and not antimatter… it touches directly on why stars, galaxies, and we ourselves exist at all.” Hamada explains, “Basically, this collapse produces a lot of particles… the right-handed neutrinos are special because their decay can naturally generate the imbalance… they are the parents of all matter in the universe today, while the knots can be thought of as our grandparents.” Eto notes, “Cosmic strings are a kind of topological soliton… our result isn’t tied to the model’s specifics… we see this as an important step toward future developments.” Nitta adds, “The next step is to refine theoretical models… upcoming gravitational-wave experiments… will be able to test whether the Universe really passed through a knot-dominated era.”

The work, published in Physical Review Letters, positions knots as crucial to matter’s origin, tying together particle physics puzzles and cosmic evolution.

Source: EurekAlert! Link: https://www.eurekalert.org/news-releases/1102836