In holographic AdS/CFT duality, tiny “baby universes” were usually thought to have zero entropy. A new analysis using Haar random coding shows their degrees of freedom are inaccessible to any single boundary observer — resolving the cloning and singularity fate paradoxes. In fact, the same heavy particle that creates geometry also plays the role of the “observer”, determining the universe’s state. So the baby universe's entropy becomes observer-dependent — much like a quantum secret you can’t read by looking at only part of the system.
According to one physical hypothesis, our voluminous world might be a projection from a flat surface. From such a Universe, tiny closed bubbles — baby universes — sometimes pinch off. For a long time, they were thought to be empty, devoid of internal diversity.
It turned out that the information inside them is scattered, like shards of a broken mirror. Each external observer sees only the reflection in their own shard — which means the degree of disorder is high, and the full picture is inaccessible to anyone. This explains why no one can peer into a black hole or grasp what's going on in curved spacetime during collapse.
This approach resolves old paradoxes like the disappearance of information. Hawking was the first to ponder these baby universes, while Maldacena and Susskind built a holographic model.
🎯 The idea of tiny universes first emerged in Stephen Hawking's work, but was long considered mathematical exotica.
🎬 In science fiction, similar ideas play out in the movie 'Interstellar,' where other dimensions opened up behind a bookshelf.