Microscopic origin of de Sitter entropy

TL;DR

This paper demonstrates that soft scalar gravitational modes fully account for the de Sitter entropy, establishing the proportionality coefficient and deriving the de Sitter temperature from scalar quantum field theory.

Contribution

It provides a concrete calculation showing soft scalar modes explain de Sitter entropy with the correct numerical factor, linking horizon microstates to quantum field theory.

Findings

Soft scalar gravitational modes account for the full de Sitter entropy.

The correct proportionality coefficient between entropy and horizon area is established.

De Sitter temperature naturally emerges from scalar quantum field theory.

Abstract

It has been argued recently that the entropy of black holes might be associated with soft scalar, graviton and photon states at the event horizon, as number of such possible soft states is proportional to the horizon area. However, the coefficient of proportionality between the number of soft states and the horizon area of a black hole has not been established. Here, similar arguments are applied to de Sitter spacetime and it is shown that soft scalar gravitational modes account for the full de Sitter entropy $S=\frac{1}{4}M_{P}^{2}A$ with the correct numerical prefactor in front of the horizon area. We also find how the value of de Sitter temperature naturally emerges in the treatment of a scalar quantum field theory on the planar patch of $dS_{4}$.