Vacuum Energy: Cosmological Constant or Quintessence?

Abstract

For a flat universe presently dominated by smooth energy, either cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of smooth energy to matter energy ${\mathcal{R}}_0$. Identifying the normalized collapsed fraction as a conditional probability for habitable galaxies, we observe that the observed present ratio ${\mathcal{R}}_0\sim 2$ is likely in LCDM, but more likely in QCDM. Inverse application of Bayes' Theorem makes the Anthropic Principle a predictive scientific principle: the data implies that the prior probability for ${\mathcal{R}}_0$ must be essentially flat over the anthropically allowed range. Interpreting this prior as a distribution over {\em theories} lets us predict that any future theory of initial conditions must be indifferent to ${\mathcal{R}}_0$. This application of the Anthropic Principle does not demand the existence of other universes.

17 pages AAS LATEX, including 2 tables, 3 figures (Postscript)

References in corpus (4)

• On likely values of the cosmological constant
• A Priori Probability Distribution of the Cosmological Constant
• On the generalized Legendre transform and monopole metrics
• Eternal inflation, black holes, and the future of civilizations

Cited by in corpus (9)

• Cosmological consequences of a Chaplygin gas dark energy
• Cosmological constraints on quintessential halos
• Some Observational Consequences of Brane World Cosmologies
• Quintessence, Cosmology, and Fanaroff-Riley Type IIB Radio Galaxies
• Quintessence Cosmology and the Cosmic Coincidence
• The Cosmic Coincidence as a Temporal Selection Effect Produced by the Age Distribution of Terrestrial Planets in the Universe
• Tracking Quintessence Would Require Two Cosmic Coincidences
• Observed Smooth Energy Fitted by Parametrized Quintessence
• X-fluid and viscous fluid in D-dimensional anisotropic integrable cosmology