Cosmological dynamics of multifield dark energy
Résumé
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.
Mots clés
phase space: analysis
space-time: expansion
expansion: acceleration
dark energy
background
attractor
geometry
trajectory
de Sitter
stability
quintessence
boundary condition
cosmological model: parameter space
spin
numerical calculations
field theory: scalar: multiple
velocity: acoustic
perturbation: linear