Super-inflation and generation of first order vector perturbations in ELKO

TL;DR

This paper demonstrates that in an ELKO-driven super-inflation model, first order vector perturbations can be generated and remain nearly scale invariant, with amplitudes smaller than scalar perturbations, offering new insights into early universe anisotropies.

Contribution

The study introduces a model where ELKO spinors generate persistent, nearly scale-invariant vector perturbations during super-inflation, a novel mechanism in early universe cosmology.

Findings

Vector perturbations do not decay on super-Hubble scales.

Vector perturbations are nearly scale invariant.

Amplitude of vector perturbations is smaller than scalar perturbations.

Abstract

In this work we construct a model where the first order vector perturbations can be generated during inflationary expansion. For the non-standard spinors, known as ELKO, we show that the components of the first order perturbed energy-momentum tensor of the ELKO is non-zero for pure vector part of the metric perturbation ($B_{i}$). We show that vector perturbations do not decay in the super-Hubble scale and for a specific super-inflation background model we show that the vector perturbations are nearly scale invariant, while its amplitude is smaller than the primordial scalar perturbations. We also comment on the generation of vorticity.