On efforts to decouple early universe cosmology and quantum gravity phenomenology

TL;DR

This paper explores the challenges and proposals for studying quantum gravity effects in the early universe, discussing the limitations of inflationary models and introducing a new 'generalized cosmic censorship' principle as an alternative approach.

Contribution

It proposes the 'generalized cosmic censorship' principle as a novel framework for early universe quantum gravity phenomenology, contrasting it with existing conjectures and addressing foundational issues.

Findings

Disputes the effectiveness of inflationary dilution in quantum gravity phenomenology.

Introduces the 'generalized cosmic censorship' principle as an alternative approach.

Highlights foundational concerns in effective field theory for cosmology.

Abstract

The Big Bang singularity in standard model cosmology suggests a program of study in 'early universe' quantum gravity phenomenology. Inflation is usually thought to undermine this program's prospects by means of a dynamical diluting argument, but such a view has recently been disputed within inflationary cosmology, in the form of a 'trans-Planckian censorship' conjecture. Meanwhile, trans-Planckian censorship has been used outside of inflationary cosmology to motivate alternative early universe scenarios that are tightly linked to ongoing theorizing in quantum gravity. Against the resulting trend toward early universe quantum gravity phenomenology within and without inflation, Ijjas and Steindhardt suggest a further alternative: a 'generalized cosmic censorship' principle. I contrast the generalized cosmic censorship principle with the logic of its namesake, the cosmic censorship conjectures. I also remark on foundational concerns in the effective field theory approach to cosmology beyond the standard model, which would be based on that principle.