Fundamentals of The Multiverse
Images: Conceptual renderings of what Multiverses might look like
Andrei Linde at Stanford has brought forward the cosmological model of a multiverse, which he calls the “self-reproducing inflationary universe.” The theory is based on Alan Guth’s inflation model, and it includes multiple universes woven together in some kind of spacetime foam. Each universe exists in a closed volume of space and time. Linde’s model, based on advanced principles of quantum physics, defies easy visualisation. Quite simplified, it suggests quantum fluctuations in the universe’s inflationary expansion period to have a wavelike character. Linde theorises that these waves can “freeze” atop one another, thus magnifying their effect.
The stacked-up quantum waves can in turn create such intense disruptions in scalar fields -the underlying fields that determine the behaviour of elementary particles- that they exceed a critical mass and start procreating new inflationary domains. The multiverse, Linde contends, is like a growing fractal, sprouting inflationary domains, with each domain spreading and cooling into a new universe.
If Linde is correct, our universe is just one of the sprouts. The theory neatly straddles two ancient ideas about the universe: that it had a definite beginning, and that it had existed forever. In Linde’s view, each particular part of the multiverse, including our part, began from a singularity somewhere in the past, but that singularity was just one of an endless series that was spawned before it and will continue after it.