Regulating Eternal Inflation

TL;DR

The paper argues that eternal inflation can be understood holographically as a finite-state quantum system governed by CDL instantons, rather than a global fractal multiverse. By identifying de Sitter space with a finite set of states bounded by its Gibbons–Hawking entropy $S_{GH}$ and introducing two Hamiltonians $H$ and $P^0$, the authors show that local observers experience transitions that obey detailed balance within a finite Hilbert space. They analyze both $V_T>0$ and $V_T<0$ cases, deriving implications for tunneling between dS vacua and to Big Crunch regions, supported by numerical results indicating that flat-space limits are not approached smoothly. The work suggests a regulator for eternal inflation and explores consequences for the string landscape and Cosmological SUSY Breaking, arguing that a finite-state description can regularize global questions while preserving local observational physics. If correct, these ideas provide a principled alternative to volume-weighted measures and offer testable insights into which vacua dominate in a fundamental theory of quantum gravity.

Abstract

We present an interpretation of the physics of space-times undergoing eternal inflation by repeated nucleation of bubbles. In many cases the physics can be interpreted in terms of the quantum mechanics of a system with a finite number of states. If this interpretation is correct, the conventional picture of these space-times is misleading.