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

Leonard Susskind

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.

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

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.
Paper Structure (17 sections, 50 equations, 1 figure)

This paper contains 17 sections, 50 equations, 1 figure.

Table of Contents

  1. Introduction
  2. Time-Reversal With or Without Clocks
  3. The System
  4. The Clock
  5. Time Reversal of the Clock
  6. Projection Operators
  7. Spontaneous Symmetry Breaking
  8. Breakdown of Clustering
  9. Gauging ${\cal{Z}}_2$
  10. Projection Operators
  11. Time-reversal in de Sitter Space
  12. Static Patch Holography
  13. Clocks in the Static Patch
  14. The Puzzle
  15. Gauging $CT$ and Dressing C
  16. ...and 2 more sections

Figures (1)

  • Figure 1: