Sharp Predictions from Eternal Inflation Patches in D-brane Inflation

TL;DR

This paper uses numerical simulations of D-brane inflation to identify eternal inflation patches, leading to precise predictions for primordial perturbation properties that can be tested through cosmological observations.

Contribution

It provides the first detailed numerical analysis linking string landscape measures with observable inflationary predictions.

Findings

Scalar tilt of 0.936 predicted

Running of scalar tilt is -0.00103

Tensors and non-Gaussianity are undetectably small

Abstract

We numerically generate the six-dimensional landscape of D3-brane inflation and identify patches of eternal inflation near sufficiently flat inflection points of the potential. We show that reasonable measures that select patches of eternal inflation in the landscape yield sharp predictions for the spectral properties of primordial perturbations on observable scales. These include a scalar tilt of .936, a running of the scalar tilt -.00103, undetectably small tensors and non-Gaussianity, and no observable spatial curvature. Our results explicitly demonstrate that precision cosmology probes the combination of the statistical properties of the string landscape and the measure implied by the universe's quantum state.