The effective Lagrangian of dark energy from observations

Abstract

Using observational data on the expansion rate of the universe (H(z)) we constrain the effective Lagrangian of the current accelerated expansion. Our results show that the effective potential is consistent with being flat i.e., a cosmological constant; it is also consistent with the field moving along an almost flat potential like a pseudo-Goldstone boson. We show that the potential of dark energy does not deviate from a constant at more than 6% over the redshift range 0 < z < 1. The data can be described by just a constant term in the Lagrangian and do not require any extra parameters; therefore there is no evidence for augmenting the number of parameters of the LCDM paradigm. We also find that the data justify the effective theory approach to describe accelerated expansion and that the allowed parameters range satisfy the expected hierarchy. Future data, both from cosmic chronometers and baryonic acoustic oscillations, that can measure H(z) at the % level, could greatly improve constraints on the flatness of the potential or shed some light on possible mechanisms driving the accelerated expansion. Besides the above result, it is shown that the effective Lagrangian of accelerated expansion can be constrained from cosmological observations in a model-independent way and that direct measurements of the expansion rate H(z) are most useful to do so.

9 pages, 3 figures, JCAP submitted. This paper presents a reconstruction of the dark energy potential. It is a companion to Moresco et al. 2012a, which presents new H(z) results and Moresco et al. 2012b, which provides cosmological parameter constraints

References in corpus (6)

• Dynamics of dark energy
• Dark Energy and the Accelerating Universe
• A 3% Solution: Determination of the Hubble Constant with the Hubble Space Telescope and Wide Field Camera 3
• The Effective Field Theory of Inflation
• Reconstructing Dark Energy
• Effective Field Theory for Inflation

Cited by in corpus (11)

• Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z$\sim$2
• The Effective Field Theory of Dark Energy
• Dark Energy or Modified Gravity? An Effective Field Theory Approach
• New constraints on cosmological parameters and neutrino properties using the expansion rate of the Universe to z~1.75
• The Clustering of Galaxies in the SDSS-III DR9 Baryon Oscillation Spectroscopic Survey: Testing Deviations from $\Lambda$ and General Relativity using anisotropic clustering of galaxies
• Effective Field Theory of Dark Energy: a Dynamical Analysis
• Cosmological Implications of the Effective Field Theory of Cosmic Acceleration
• Probing the constancy of the speed of light with future galaxy survey: the case of SKA and Euclid
• Recovering a redshift-extended VSL signal from galaxy surveys
• The parameter space of Cubic Galileon models for cosmic acceleration
• Einstein Spaces Modeling Nonminimal Modified Gravity