Cosmological dynamics of multifield dark energy

TL;DR

This paper investigates the complex dynamics of multifield dark energy models with nongeodesic trajectories, identifying conditions for late-time acceleration and stability, and comparing theoretical predictions with cosmological observations.

Contribution

It provides a combined numerical and analytical analysis of multifield dark energy with spinning trajectories, extending single-field models and deriving bounds on parameters for viability.

Findings

Identified attractor solutions leading to late-time acceleration.

Derived bounds on model parameters ensuring stability and acceleration.

Compared model predictions with cosmological constraints.

Abstract

We numerically and analytically explore the background cosmological dynamics of multifield dark energy with highly nongeodesic or "spinning" field-space trajectories. These extensions of standard single-field quintessence possess appealing theoretical features and observable differences from the cosmological standard model. At the level of the cosmological background, we perform a phase-space analysis and identify approximate attractors with late-time acceleration for a wide range of initial conditions. Focusing on two classes of field-space geometry, we derive bounds on parameter space by demanding viable late-time acceleration and the absence of gradient instabilities, as well as from the de Sitter swampland conjecture.