Tracking Quintessence Would Require Two Cosmic Coincidences

Abstract

Good tracking requires that the quintessence energy fraction slowly increase while the roll $\lambda \equiv -d\ln V/\varkappa d\varphi$ slowly decreases, but is not yet truly slow-rolling. The supernova bound on the present quintessence equation of state requires either (1) a cosmological constant or other fine-tuned "crawling quintessence" or (2) "roll-over quintessence" that tracked until recently, but now became slow rolling, because of a sharp increase in potential curvature. Thus, fine-tuning is required by constant equation of state and inverse power potentials, but can be avoided by the SUGRA and Skordis-Albrecht potentials and other good trackers, provided quintessence energy domination and slow roll {\em both} began only recently. This makes the time in which we live special in {\em two} respects.

10 pages, including 2 figures, 3 tables

References in corpus (1)

• Cosmology and the Fate of Dilatation Symmetry

Cited by in corpus (23)

• Constraints on the redshift dependence of the dark energy potential
• Nonlocal Cosmology
• Thawing quintessence with a nearly flat potential
• Ghosts, Instabilities, and Superluminal Propagation in Modified Gravity Models
• Loop cosmological dynamics and dualities with Randall-Sundrum braneworlds
• Quintessence reconstructed: new constraints and tracker viability
• Non-minimal quintessence and phantom with nearly flat potentials
• Quintom dark energy models with nearly flat potentials
• A comparison of structure formation in minimally and non-minimally coupled quintessence models
• Extended quintessence with an exponential coupling
• Observational constraints on thawing quintessence models
• Massive Photon and Dark Energy
• Approaching Lambda without fine-tuning
• Scaling solutions in scalar-tensor cosmologies
• The Cosmic Coincidence as a Temporal Selection Effect Produced by the Age Distribution of Terrestrial Planets in the Universe
• Coupling Quintessence to Inflation in Supergravity
• Exploring Parameter Constraints on Quintessential Dark Energy: the Inverse Power Law Model
• Unsuccessful cosmology with Modified Gravity Models
• Dark-Energy Dynamics Required to Solve the Cosmic Coincidence
• Can we ever distinguish between quintessence and a cosmological constant?
• Constraints on Quintessence From Using Cosmological Data
• Approximate $w_{\varphi }\sim {\Omega }_{\varphi }$ Relations in Quintessence Models
• Gravitational vacuum energy in our recently accelerating universe