https://en.wikipedia.org/wiki/Many-worlds_interpretation

https://en.wikipedia.org/wiki/Calculating_Space -> https://en.wikipedia.org/wiki/Cellular_automaton -> related to the latter https://writings.stephenwolfram.com/2026/01/what-is-ruliolog... and https://www.wolframscience.com/nks/ fit in as well.

Maybe https://en.wikipedia.org/wiki/Indra's_Pearls_(book) , too.

Furthermore https://en.wikipedia.org/wiki/Indra's_net for a much older concept.

For one of many (hard) sci-fi novels about this Cosm by Gregory Benford comes to mind.