Disformally self-tuning gravity

TL;DR

This paper introduces a new class of scalar-tensor gravity theories with disformal matter couplings that can dynamically cancel the cosmological constant in cosmological models, extending previous self-tuning models.

Contribution

It generalizes the Fab Four model by incorporating disformal couplings to matter, enabling self-tuning of the cosmological constant in a broader class of theories.

Findings

Successfully extended the Fab Four model with disformal couplings.

Constructed a new class of self-tuning scalar-tensor theories.

Demonstrated the ability to cancel the cosmological constant on FLRW backgrounds.

Abstract

We extend a previous self-tuning analysis of the most general scalar-tensor theory of gravity in four dimensions with second order field equations by considering a generalized coupling to the matter sector. Through allowing a disformal coupling to matter we are able to extend the Fab Four model and construct a new class of theories that are able to tune away the cosmological constant on Friedmann-Lemaitre-Robertson-Walker backgrounds.