The most general cosmological dynamics for ELKO Matter Fields

TL;DR

This paper derives the most general cosmological dynamics for ELKO matter fields, revealing that additional dynamical terms can lead to anisotropic universes and challenge the compatibility of ELKO matter with the cosmological principle.

Contribution

It provides a comprehensive formulation of ELKO matter dynamics in curved spacetimes, including torsion, and explores their cosmological implications.

Findings

New dynamical terms can cause ELKO matter to be incompatible with isotropic cosmology.

Anisotropic universes are necessary to accommodate the most general ELKO dynamics.

ELKO matter's behavior is significantly affected by extended gravitational couplings.

Abstract

Not long ago, the definition of eigenspinors of charge-conjugation belonging to a special Wigner class has lead to the unexpected theoretical discovery of a form of matter with spin 1/2 and mass dimension 1, called ELKO matter field; ELKO matter fields defined in flat spacetimes have been later extended to curved and twisted spacetimes, in order to include in their dynamics the coupling to gravitational fields possessing both metric and torsional degrees of freedom: the inclusion of non-commuting spinorial covariant derivatives allows for the introduction of more general dynamical terms influencing the behaviour of ELKO matter fields. In this paper, we shall solve the theoretical problem of finding the most general dynamics for ELKO matter, and we will face the phenomenological issue concerning how the new dynamical terms may affect the behaviour of ELKO matter; we will see that new effects will arise for which the very existence of ELKO matter will be endangered, due to the fact that ELKOs will turn incompatible with the cosmological principle. Thus we have that anisotropic universes must be taken into account if ELKOs are to be considered in their most general form.