First-order phase transitions in the early universe give birth to bubbles of true vacuum. Usually, their evolution is described classically, but if the transition breaks symmetry, the bubbles acquire an enormous number of internal quantum states (degeneracy). This not only speeds up their appearance but also forces them to be born in a maximally entangled state — like a choir singing in perfect unison. When they merge, this entanglement leads to macroscopic differences from the classical scenario, including the emergence of new, previously unaccounted-for gravitational waves.
The early Universe was hot and dense. Within it, like in boiling water, bubbles of a new state of space were born. Usually they are considered simple, but some harbored a gigantic number of hidden 'patterns' — microscopic states, or entropy. It’s like a soap bubble whose surface shimmers not with seven colors, but with billions of shades.
When such bubbles collide, their entanglement does not vanish instantly but instead alters the merger process. This imprints on gravitational waves — ripples in spacetime. Unlike the merger of black holes, where information seemingly disappears, bubbles leave a distinct quantum signature in the waves — an echo of their 'multitude'.
Future detectors, similar to the one created by Rainer Weiss, will be able to capture these signals. Thus we will peer for the first time into the quantum 'personality' of space.
🎯 Each bubble was born at once in all possible states — as if a tossed coin landed both heads and tails simultaneously. The complexity of each bubble was astronomical: the number of its microstates exceeds the number of atoms in the observable Universe.
🎬 Sci-fi often plays with the theme of multiple universes, but here the 'bubble universes' are also quantum-entangled — as if they share a common memory of the moment of creation.