Invisible Walls of the Early Universe express
Hot syrup cools quickly: crystals solidify at different points simultaneously, and the boundaries between them become thin walls. A similar process may have occurred in the first moments after the Big Bang — a special field permeating the cosmos cracked, creating domain walls. These walls separated regions with different properties, like invisible partitions. Colliding and vanishing, the walls shook spacetime itself, generating gravitational waves.
But the walls are interesting not just for the ripples. They hold a secret related to why we exist at all. Our world is made of matter, even though at the moment of creation there were equal amounts of particles and antiparticles. For matter to win, special conditions are needed that break the symmetry between particles and their mirror counterparts. Domain walls could have been exactly the places where such asymmetry hid. However, gravitational waves alone won't tell us whether this balance was broken: they only show that the walls existed.
Here the electron comes to the rescue. According to the theory, the same field that created the walls should slightly distort the electron's shape — giving it a so-called electric dipole moment (a tiny elongation along one axis). The electron ceases to be a perfect sphere and becomes slightly stretched. This distortion is extremely small, but modern instruments can detect it. The authors compared which theory parameters could produce both noticeable gravitational waves and a measurable electron distortion. It turns out that existing experiments already rule out some possibilities, and future, more precise ones could probe almost the entire region where new observatories like SKA hope to catch a signal.
Thus, two completely different tools, a cosmic detector of spacetime ripples and a laboratory trap for electrons, combine into a single picture. They are like two ears listening to the same whisper from the past: gravitational waves carry the rhythm of vanishing walls, while the electron preserves the imprint of their internal asymmetry. Together, they can tell how fragile matter survived and became stars, planets, and us.
If the electron had a noticeable electric dipole moment, it could be imagined as a tiny compass needle that always points in one direction — except it responds not to a magnetic field but to an electric one.
The idea of invisible walls separating realities is explored in China Miéville's novel 'The City & the City'—there, two cities exist in the same space, but residents do not notice each other.