Ultraviolet sensitivity of the cosmological sequester

TL;DR

This paper critically examines the ultraviolet sensitivity of the cosmological sequester mechanism, analyzing quantum corrections and their impact on the model's ability to decouple the cosmological constant from quantum loops.

Contribution

It provides a detailed review of various formulations of the sequester model and assesses the effects of quantum corrections on its effectiveness.

Findings

Quantum corrections are generally smaller than the cosmological term induced by graviton loops.

In the most developed formulation, dressing effects can be absorbed into field rescaling, preserving sequestration.

Formulations lacking proper graviton loop sequestration exhibit additional failures due to quantum dressing.

Abstract

We revisit the "sequester" proposal of Kaloper, Padilla and collaborators, in which the amplitude of the cosmological constant is decoupled from large contributions due to loops containing Standard Model particles. We review the different formulations of the model that have appeared in the literature, and estimate the importance of a particular class of quantum corrections-those that dress the interaction between the "rigid" scalars and infrared properties of the spacetime such as its 4-volume and integrated curvature. In formulations that do not adequately sequester graviton loops we argue that dressing of these interactions causes further failures of complete sequestration. We estimate the size of the effect and find that it is typically smaller than the cosmological term directly induced by loops containing a single virtual graviton. Meanwhile, in the most developed formulation of the scenario (where a rigid scalar couples to the Gauss-Bonnet density), this dressing can be absorbed into a rescaling of the rigid fields and is therefore harmless.