Long Inflation Screens Euclidean-Wormhole Initial States

TL;DR

Euclidean wormholes can set initial states for inflation, but extended inflationary periods diminish their observable signatures in the CMB, establishing a bound on inflation duration.

Contribution

The paper derives a quantitative bound on inflation duration based on the fading of Euclidean wormhole memory signatures in the CMB.

Findings

Residual signatures are confined to a comoving edge $k_w=a_iM$

Detectable imprints occur only near-minimal inflation or within the observable window

Longer inflation drives perturbations to the Bunch--Davies prediction

Abstract

Euclidean wormholes can prepare inflation in non--Bunch--Davies initial states, but long Lorentzian expansion screens this memory from the CMB. We derive a visibility bound for Euclidean-matched Bogoliubov data: the pivot excitation satisfies $|\beta_*| \lesssim e^{-2N_{\rm pre}}$, and smooth Euclidean filters confine residual signatures to a comoving edge $k_w=a_iM$. Only near-minimal inflation, or an edge inside the observable window, leaves detectable scalar, tensor, and higher-point imprints. For longer inflation, wormhole-prepared perturbations are driven to the Bunch--Davies prediction. Euclidean memory therefore, becomes a quantitative bound on inflationary duration, with direct targets in CMB polarization and large-scale structure: the longer inflation lasts, the less of the wormhole remains on the sky.