Trans-Planckian signals from the breaking of local Lorentz invariance

TL;DR

This paper explores how breaking local Lorentz invariance at tiny scales could produce unique signals in the primordial power spectrum, with some corrections mimicking effects from inflationary field states.

Contribution

It identifies specific irrelevant operators that lead to distinctive, non-oscillatory corrections in the primordial power spectrum, linking Lorentz violation to observable inflationary signals.

Findings

Certain operators produce non-oscillatory spectrum corrections

Some corrections match effects from inflationary field states

Breakdown of Lorentz invariance can leave detectable imprints

Abstract

This article examines how a breakdown of a locally Lorentz invariant, point-like description of nature at tiny space-time intervals would translate into a distinctive set of signals in the primordial power spectrum generated by inflation. We examine the leading irrelevant operators that are consistent with the spatial translations and rotations of a preferred, isotropically expanding, background. A few of the resulting corrections to the primordial power spectrum do not have the usual oscillatory factor, which is sometimes taken to be characteristic of a "trans-Planckian" signal. Perhaps more interestingly, one of these leading irrelevant operators exactly reproduces a correction to the power spectrum that occurs in effective descriptions of the state of the field responsible for inflation.