Scalar tachyons in the de Sitter universe

TL;DR

This paper constructs de Sitter covariant tachyonic quantum fields with negative squared mass, revealing their properties, anomalies, and relation to massless minimally coupled fields, advancing understanding of quantum fields in curved spacetime.

Contribution

It introduces a new class of local, de Sitter covariant tachyonic quantum fields with discrete negative mass squared, including an anomalous Klein-Gordon equation and a physical subspace.

Findings

Fields exist for discrete negative mass squared values

Anomalous covariant field used to define physical subspace

Model is local and de Sitter invariant on the physical space

Abstract

We provide a construction of a class of local and de Sitter covariant tachyonic quantum fields which exist for discrete negative values of the squared mass parameter and which have no Minkowskian counterpart. These quantum fields satisfy an anomalous non-homogeneous Klein-Gordon equation. The anomaly is a covariant field which can be used to select the physical subspace (of finite codimension) where the homogeneous tachyonic field equation holds in the usual form. We show that the model is local and de Sitter invariant on the physical space. Our construction also sheds new light on the massless minimally coupled field, which is a special instance of it.