I’m not sure I believe that the heat death of the universe really is the end of all things forever and for all time either, after reading Asimov’s The Last Question and a particularly fantastic manga oneshot adaptation by manga artist Ryul.
If you haven’t read it, I can’t recommend it more highly, and the manga version is a nice addition to the canon. I found a version narrated by the man himself on the Internet Archive, and I also found a fully voice acted audio version from the Drabblecast, also linked below.
https://en.wikipedia.org/wiki/The_Last_Question
https://www.isfdb.org/cgi-bin/title.cgi?41230
Original publication:
https://archive.org/stream/Science_Fiction_Quarterly_New_Ser...
Manga version:
https://www.mangaupdates.com/series/oo67iat/the-last-questio...
https://mangadex.org/title/f1e5d886-cc50-4cbf-ac8b-6914d9343...
https://archive.org/details/manga_The_Last_Question
Audiobook versions:
https://archive.org/details/IsaacAsimovAudioBookCollection/1...
https://www.drabblecast.org/2011/03/11/drabblecast-200-the-l...
Long story short, assuming an infinite universe post-"heat death", we'd expect to be able to find every possible arrangement of particles represented at some location, even very complex ones such as the entire universal state we observe today.
> Quantum foam or spacetime foam is a theoretical quantum fluctuation of spacetime on very small scales due to quantum mechanics. The theory predicts that at these small scales, particles of matter and antimatter are constantly created and destroyed. These subatomic objects are called virtual particles. The idea was devised by John Wheeler in 1955.
https://en.wikipedia.org/wiki/Quantum_foam
https://www.vice.com/en/article/j5yngp/the-universe-is-made-...