English

When do real observers resolve de Sitter's imaginary problem?

High Energy Physics - Theory 2026-04-16 v2 General Relativity and Quantum Cosmology

Abstract

The universal phase \rev\iiD+2\rev{\ii}^{D+2} of the Euclidean de Sitter path integral obstructs a straightforward state-counting interpretation of the Gibbons--Hawking entropy. Building on Maldacena's proposal that specific black-hole observers can reorganize this phase, we derive a general constraint on when such ``real observers'' can succeed. By distinguishing \emph{gravitational observers} from \emph{topological spectators}, we show at quadratic semiclassical order that any sector whose \emph{infrared effective} action is metric independent at the de Sitter saddle factorizes in the path integral, \Ztot=\Zgrav(obs)\Ztop\Ztot = \Zgrav^{(\text{obs})}\Ztop, so the imaginary phase persists regardless of the sector's information-processing capabilities. Using confining \SU(3)\SU(3) gauge theory and topological orders as examples, we demonstrate that an information-bearing clock is necessary but insufficient: only observers whose fluctuations share the negative modes of the conformal factor belong to the special class that can remove the de Sitter phase.

Keywords

Cite

@article{arxiv.2603.18068,
  title  = {When do real observers resolve de Sitter's imaginary problem?},
  author = {Ahmed Farag Ali},
  journal= {arXiv preprint arXiv:2603.18068},
  year   = {2026}
}

Comments

4 pages, 1 TikZ figure, RevTeX 4.2; accepted for publication in Commun. Theor. Phys, Added references

R2 v1 2026-07-01T11:26:48.945Z