Uplifting, Depressing, and Tilting Dark Energy
Eric V. Linder

TL;DR
This paper investigates dark energy models that can explain the observed acceleration patterns, finding that typical interaction models struggle to fit data unless dark energy itself crosses the phantom divide, which is physically unusual.
Contribution
It demonstrates that common interaction-based dark energy models generally fail to fit cosmological data unless dark energy crosses w=-1, highlighting the need for such crossing.
Findings
Interaction models often do not fit data well
Dark energy must cross w=-1 to match observations
Crossing w=-1 is physically unusual
Abstract
Current data in the form of baryon acoustic oscillation, supernova, and cosmic microwave background distances prefer a cosmology that accelerates more strongly than CDM at , and more weakly at . We examine dark energy physics that can accommodate this, showing that interactions (decays, coupling to matter, nonminimal coupling to gravity) fairly generically tend not to give a satisfactory solution (in terms of fitting both distances and growth) even if they enable the effective dark energy equation of state to cross . To fit the cosmological data it appears the dark energy by itself must cross , a highly unusual physical behavior.
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Taxonomy
TopicsCosmology and Gravitation Theories · Pulsars and Gravitational Waves Research · Dark Matter and Cosmic Phenomena
