What-if inflaton is a spinor condensate?

TL;DR

This paper explores the possibility that the inflaton could be a spinor condensate instead of a scalar field, analyzing its observational signatures and how it differs from canonical models, with implications for future cosmological tests.

Contribution

It introduces a spinor condensate model for inflation, compares its dynamics and observational signatures with canonical scalar field models, and suggests ways to distinguish them through future experiments.

Findings

Spinor condensate leads to identical acceleration equations as scalar fields.

The model predicts a running of the scalar spectral index consistent with WMAP.

Distinct consistency relations can be tested with future CMB and gravitational wave data.

Abstract

In the usual cosmological inflationary scenarios, the scalar field -- inflaton -- is usually assumed to be an elementary field. In this essay, we ask: What are the observational signatures, if the scalar field is a spinor condensate? and Is there a way to distinguish between the canonical scalar field and the spinor condensate driven models? In the homogeneous and isotropic background, we show that, although the dark-spinor (Elko) condensate leads to the identical acceleration equation as that of the canonical scalar field driven inflation, the dynamics of the two models are different. In the slow-roll limit, we show that the model, predicts a running of scalar spectral index consistent with the WMAP data. We show that the consistency relations between the spinor condensate and canonical scalar field driven model are different which can be tested using the future CMB and gravitational wave missions.