Constraints on the duration of inflation from entanglement entropy bounds

TL;DR

This paper derives an upper limit on the duration of inflation by applying entanglement entropy bounds to observable long-wavelength modes, linking quantum information constraints to cosmological stability.

Contribution

It introduces a novel method of constraining inflation duration using entanglement entropy bounds, connecting quantum information theory with cosmological models.

Findings

Entanglement entropy of observable modes is bounded by covariant entropy bounds.

An upper limit on inflation duration is derived from entropy considerations.

Provides insights into the stability and lifetime of de Sitter spacetime.

Abstract

Using the fact that we only observe those modes which exit the Hubble horizon during inflation, one can calculate the entanglement entropy of such long-wavelength perturbations by tracing out unobservable sub-Hubble fluctuations they are coupled to. On requiring that this perturbative entanglement entropy, which increases with time, obey the covariant entropy bound for an accelerating background, we find an upper bound on the duration of inflation. This presents a new perspective on the (meta-)stability of de Sitter spacetime and an associated lifetime for it.