An Observer in de Sitter Space, and Rereading Everett

Edward Witten

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arXiv · 2610.04804

An Observer in de Sitter Space, and Rereading Everett

Edward Witten

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Abstract

After re-examining a classic article by Hugh Everett, I will discuss the entropy of de Sitter space from the standpoint of an observer living in the space. This provides a nice example of the importance -- for certain questions -- of taking seriously the fact that in cosmology any observer is really part of the universe that is being observed. (This article has appeared in a special issue of International Journal of Modern Physics A in honor of Gerard 't Hooft.

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Edward Witten. 2026-10-03. An Observer in de Sitter Space, and Rereading Everett. https://arxiv.org/abs/2610.04804

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