QFT
In the literature: open
Microscopic count of de Sitter horizon entropy
In plain words
The horizon of an expanding universe has an entropy proportional to its area, just like a black hole. Which quantum states it counts is unknown.
Precise statement
The Gibbons-Hawking entropy of a d-dimensional de Sitter horizon is $S = A c^3/(4 G \hbar)$ with $k_B = 1$. Find a statistical system whose state count reproduces S including the one-loop logarithmic correction computed by Anninos, Denef, Law and Sun (2020).
What would settle it
A microscopic system with a derived match of the leading area term and the logarithmic correction.
Status in the literature
The static-patch algebra of observables was shown to be of von Neumann type $\mathrm{II}_{1}$ with a maximum-entropy state (Chandrasekaran, Longo, Penington, Witten 2022), without a microscopic count.
Related problems
- Special case of Holographic dual of quantum gravity in de Sitter space