Swampland Conjectures Constraints on Dark Energy from a Highly Curved Field Space

TL;DR

This paper explores how swampland conjectures constrain multifield dark energy models with curved field space, showing that effective field theory remains valid and consistent with observations despite tensions with the trans-Planckian censorship conjecture.

Contribution

It introduces a multifield dark energy model with curved field space that satisfies swampland conjectures and observational data, highlighting the interplay between TCC and SDC.

Findings

The model features a stable attractor with near constant equation of state w ≈ -1.

The apparent TCC violation occurs after the fields traverse a Planckian distance.

The SDC predicts EFT breakdown before TCC violation, ensuring consistency.

Abstract

We study the interplay of the trans-Planckian censorship conjecture (TCC) and the swampland distance conjecture (SDC) in the context of multifield dark energy in a curved field space. In this scenario, the phase of accelerated expansion is realized as non-geodesic motion in a highly-curved field space, reminiscent of models developed in the context of inflation. The model features a stable attractor solution with near constant equation of state $w\simeq -1$, and predicts that the current era of accelerated expansion is eternal. The latter implies an eventual conflict with the TCC, which holds that the duration of any epoch of cosmic acceleration is bounded by the requirement that the large-scale observable universe is blind to Planck-scale early universe physics. This tension can be resolved by an interplay with the distance conjecture: for suitable parameter values, the apparent violation of the TCC occurs well after the fields have traversed a Planckian distance. The SDC then predicts a breakdown of the effective field theory (EFT) before the TCC can be violated. We derive the constraints on the model arising from the SDC+TCC and the de Sitter conjecture. We demonstrate that the model can be consistent with both swampland conjectures and observational data from Planck 2018 and the Dark Energy Spectroscopic Instrument.