2026-04-17T19:05:45Zhttps://recercat.cat/oai/request
oai:recercat.cat:2445/1275092025-12-05T16:10:15Zcom_2072_1057col_2072_478904col_2072_478917
RECERCAT author Jiménez, Raúl (Jiménez Tellado) author Talavera Sánchez, Pedro author Verde, Licia author Moresco, Michele author Cimatti, Andrea author Pozzetti, Lucia 2019-01-22T12:18:51Z2019-01-22T12:18:51Z20122019-01-22T12:18:52Z 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. (c) IOP Publishing and Sissa Medialab, 2012 info:eu-repo/semantics/openAccess Fenomenologia Energia fosca (Astronomia) Cosmologia Phenomenology Dark energy (Astronomy) Cosmology The effective Lagrangian of dark energy from observations info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion