On the consistency of Constraints in Matter Field Theories

TL;DR

This paper investigates how causality and equivalence principles impose restrictions on the background settings of matter field theories, revealing that only simple theories remain consistent under these constraints.

Contribution

It demonstrates that complex matter field theories generally become inconsistent due to causality and equivalence constraints, highlighting the special status of simpler theories.

Findings

Complex matter theories are often inconsistent under causality constraints.

Simple matter field theories can satisfy causality and equivalence principles.

Constraints limit the background settings for matter field theories.

Abstract

We consider how the principles of causality and equivalence restrict the background in which matter field theories are defined; those constraints develop in restrictions for these matter field theories: the simplest matter field theory aside, all other less simple matter field theories are too complex therefore resulting to be inconsistent in general instances.