Assisted Fibre Inflation in Perturbative LVS

TL;DR

This paper introduces a multi-field fibre inflation model within type IIB large volume compactifications, demonstrating how multiple moduli collectively enable inflation consistent with current cosmological observations.

Contribution

It presents a novel multi-field fibre inflation scenario with assisted dynamics, reducing individual field excursions and aligning with recent experimental bounds.

Findings

Multi-field dynamics suppress trans-Planckian inflaton displacements.

Multiple moduli collectively produce cosmological observables within experimental bounds.

Numerical models show compatibility with recent ACT experiment data.

Abstract

We propose a multi-field fibre inflation scenario in type IIB perturbative large volume compactifications, showing that the multi-field dynamics suppresses trans-Planckian displacements of the canonical inflaton. Considering a concrete K3-fibred Calabi-Yau (CY) threefold with $h^{1,1}({\rm CY})=3$ and having certain underlying symmetries, we show that the presence of multi-fibre moduli creates an assisted inflation scenario where multiple moduli collectively help in producing the cosmological observables consistent with the current experimental bounds. We further argue that individual field range excursions $(\Delta\phi_n)$ corresponding to each of the inflaton fields can be estimated as $\Delta\phi_n = \Delta\phi/\sqrt{n}$, where $\Delta\phi$ denotes the effective single-field inflaton range needed to generate the desired cosmological observables, and $n$ is the number of moduli assisting the multi-fibre inflation. We also present various numerical benchmark models consistently producing cosmological observables in light of the recent ACT experiments.