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arXiv · 2601.01666

More About the Spontaneous Breaking of Time Reversal in de Sitter Space

Leonard Susskind
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Abstract

It is widely thought that the quantum theory of de Sitter space requires the existence of a physical observer in the static patch. What exactly is meant by an observer is unclear; it could be anything from a few photons with energy just above the Gibbons-Hawking temperature to a gravitationally bound cluster of galaxies. In a recent note I explained that the need for observers can arise from the spontaneous breaking of time-reversal symmetry. This longer paper expands on the subject, filling in conceptual arguments that were implicit but not explicitly stated in the earlier paper.

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Leonard Susskind. 2026-01-04. More About the Spontaneous Breaking of Time Reversal in de Sitter Space. https://arxiv.org/abs/2601.01666

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