Cosmological constraints from UV/IR mixing

TL;DR

This paper explores how UV/IR mixing in holography imposes bounds on scalar field ranges in cosmology, challenging inflation models and linking extra dimensions to observable ratios.

Contribution

It derives a new bound on scalar field ranges from UV/IR mixing and connects extra dimensions to the tensor-to-scalar ratio in inflation.

Findings

Bounds challenge $ ext{α}$-attractors and modular inflation.

Relation between extra dimensions and tensor-to-scalar ratio.

Implications for holographic cosmology models.

Abstract

Holography and entropy bounds suggest that the ultraviolet (UV) and infrared (IR) cutoffs of gravitational effective theories are related to one another as a form of UV/IR mixing. Motivated by this, we derive a bound on the allowed scalar field range in theories with cosmic horizons. We show how this bound challenges several inflationary scenarios, such as $\alpha$-attractors and modular-invariant inflation. Besides, we find a relation between the number of extra spatial dimensions and the tensor-to-scalar ratio.