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Title: Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study

Despite the many efforts, our theoretical understanding of the ultimate nature of the dark energy component of the universe still lags well behind the astounding experimental evidence achieved from the increasingly sophisticated observational tools at our disposal. While the canonical possibility is a strict cosmological constant, or rigid vacuum energy density ρ{sub Λ} = const., the exceeding simplicity of this possibility lies also at the root of its unconvincing theoretical status, as there is no explanation for the existence of such constant for the entire cosmic history. Herein we explore general models of the vacuum energy density slowly evolving with the Hubble function H and/or its time derivative, ρ{sub Λ} = ρ{sub Λ}(H, H-dot ). Some of these models are actually well-motivated from the theoretical point of view and may provide a rich phenomenology that could be explored in future observations, whereas some others have more limitations. In this work, we put them to the test and elucidate which ones are still compatible with the present observations and which ones are already ruled out. We consider their implications on structure formation, in combination with data on type Ia supernovae, the Cosmic Microwave Background, the Baryonic Acoustic Oscillations, and the predicted redshift distribution of cluster-sizemore » collapsed structures. The relation of these vacuum models on possible evidence of dynamical dark energy recently pointed out in the literature is also briefly addressed.« less
Authors:
;  [1] ;  [2]
  1. High Energy Physics Group, Dept. ECM, and Institut de Ciències del Cosmos, Univ. de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Catalonia (Spain)
  2. Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efesiou 4, 11527, Athens (Greece)
Publication Date:
OSTI Identifier:
22382042
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AUGMENTATION; BARYONS; COSMOLOGICAL CONSTANT; ENERGY DENSITY; FUNCTIONS; NONLUMINOUS MATTER; OSCILLATIONS; RED SHIFT; RELICT RADIATION; SUPERNOVAE; UNIVERSE