Vacuum bubbles arising during first-order phase transitions are usually described classically. However, with spontaneous symmetry breaking, a high degree of degeneracy of microstates emerges. This boosts the transition rate and leads to bubbles being born in a maximally entangled quantum state — a symmetric superposition of many classical configurations. The internal entanglement persists all the way to the merger, making the quantum dynamics of merging macroscopically distinct from any classical analogs. These differences are imprinted as macroscopic features in the spectrum of relic gravitational waves. Thus, microstate entanglement becomes a qualitatively new source of gravitational waves. The effect has been quantified and compared to the fast memory-load effect in black hole mergers.
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.