Long Inflation Screens Euclidean-Wormhole Initial States

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.