IPMU Colloquium

Speaker: Andrei Linde (Stanford U)
Title: Universe or Multiverse?
Date (JST): Wed, Jan 19, 2022, 10:30 - 12:00
Place: Zoom
Abstract: Cosmological observations show that the universe is very uniform on the maximally large scale accessible to our telescopes. The simplest theoretical explanation of this uniformity is provided by the inflationary theory. I will briefly describe the status of this theory in view of recent observational data provided by the Planck satellite and by the BICEP/Keck observations. Rather paradoxically, this theory predicts that on extremely large scales, much greater than what we can see now, the world may look totally different. Instead of being a single spherically symmetric balloon, our universe may look like a "multiverse," a collection of many different exponentially large balloons ("universes") with different laws of low-energy physics operating in each of them. Even more complicated possibilities emerge if one attempts to describe the multiverse in the context of quantum cosmology. Is it physics or metaphysics? Is there any way to confirm that we live in the multiverse?