Tuesday, February 21, 2017

"From Eternity to Here" - Sean Carroll

Amazon Link

Just finished Sean Carroll's 2011 book, which - after an exhaustive exploration of all other options - locates the origin of 'the arrow of time' in the quantum-fluctuation emergence of super-low-entropy 'baby universes' from a preceding high-entropy de Sitter universe.

Yep, that would be the baby universe in which I'm sitting writing this post.

This may seem extravagant, to explain why eggs produce omelettes but not the reverse, but he refutes all the simpler explanations.

It presently seems unclear, however, whether a de Sitter universe could even make baby universes, absent a better theory of quantum gravity.

Carroll's latest thinking tends in a different direction, suggesting that framing the issue within the spacetime realm may itself be a mistake; the true nature of reality may be Hilbert space with Schrödinger equation dynamics. Spacetime, with its arrow of time, may be emergent.

Strange that the weirdest ideas of modern physics - the MWI, emergent spacetime - seem to be the most plausible.

This is a fine book, and an excellent introduction for the smart non-physicist to general relativity, quantum theory (QM/QFT) and cosmology.

1 comment:

  1. Actually this book is dated 2010, I read a Library copy in 2013 - I had thought that you were reading his latest book "The Big Picture.."

    It all just shows that the mixing of Hilbert Space and Spacetime needed for Quantum Gravity brings out strange new structures (and ideas) since these two mathematical ingredients are so different from each other...

    Lots more about AI and Robots in the news and radio etc. E.g. 11 am today on Radio 4 on "AI and the Real World".


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