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Title: Confronting the relaxation mechanism for a large cosmological constant with observations

Abstract

In order to deal with a large cosmological constant a relaxation mechanism based on modified gravity has been proposed recently. By virtue of this mechanism the effect of the vacuum energy density of a given quantum field/string theory (no matter how big is its initial value in the early universe) can be neutralized dynamically, i.e. without fine tuning, and hence a Big Bang-like evolution of the cosmos becomes possible. Remarkably, a large class (F{sup n}{sub m}) of models of this kind, namely capable of dynamically adjusting the vacuum energy irrespective of its value and size, has been identified. In this paper, we carefully put them to the experimental test. By performing a joint likelihood analysis we confront these models with the most recent observational data on type Ia supernovae (SNIa), the Cosmic Microwave Background (CMB), the Baryonic Acoustic Oscillations (BAO) and the high redshift data on the expansion rate, so as to determine which ones are the most favored by observations. We compare the optimal relaxation models F{sup n}{sub m} found by this method with the standard or concordance ΛCDM model, and find that some of these models may appear as almost indistinguishable from it. Interestingly enough, this shows thatmore » it is possible to construct viable solutions to the tough cosmological fine tuning problem with models that display the same basic phenomenological features as the concordance model.« less

Authors:
; ;  [1]
  1. High Energy Physics Group, Dept. ECM, Univ. de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Catalonia (Spain)
Publication Date:
OSTI Identifier:
22280191
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2012; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BARYONS; COMPARATIVE EVALUATIONS; COSMOLOGICAL CONSTANT; COSMOLOGY; ENERGY DENSITY; GRAVITATION; OSCILLATIONS; RED SHIFT; RELAXATION; RELICT RADIATION; STRING MODELS; STRING THEORY; SUPERNOVAE; UNIVERSE

Citation Formats

Basilakos, Spyros, Bauer, Florian, and Solà, Joan. Confronting the relaxation mechanism for a large cosmological constant with observations. United States: N. p., 2012. Web. doi:10.1088/1475-7516/2012/01/050.
Basilakos, Spyros, Bauer, Florian, & Solà, Joan. Confronting the relaxation mechanism for a large cosmological constant with observations. United States. https://doi.org/10.1088/1475-7516/2012/01/050
Basilakos, Spyros, Bauer, Florian, and Solà, Joan. 2012. "Confronting the relaxation mechanism for a large cosmological constant with observations". United States. https://doi.org/10.1088/1475-7516/2012/01/050.
@article{osti_22280191,
title = {Confronting the relaxation mechanism for a large cosmological constant with observations},
author = {Basilakos, Spyros and Bauer, Florian and Solà, Joan},
abstractNote = {In order to deal with a large cosmological constant a relaxation mechanism based on modified gravity has been proposed recently. By virtue of this mechanism the effect of the vacuum energy density of a given quantum field/string theory (no matter how big is its initial value in the early universe) can be neutralized dynamically, i.e. without fine tuning, and hence a Big Bang-like evolution of the cosmos becomes possible. Remarkably, a large class (F{sup n}{sub m}) of models of this kind, namely capable of dynamically adjusting the vacuum energy irrespective of its value and size, has been identified. In this paper, we carefully put them to the experimental test. By performing a joint likelihood analysis we confront these models with the most recent observational data on type Ia supernovae (SNIa), the Cosmic Microwave Background (CMB), the Baryonic Acoustic Oscillations (BAO) and the high redshift data on the expansion rate, so as to determine which ones are the most favored by observations. We compare the optimal relaxation models F{sup n}{sub m} found by this method with the standard or concordance ΛCDM model, and find that some of these models may appear as almost indistinguishable from it. Interestingly enough, this shows that it is possible to construct viable solutions to the tough cosmological fine tuning problem with models that display the same basic phenomenological features as the concordance model.},
doi = {10.1088/1475-7516/2012/01/050},
url = {https://www.osti.gov/biblio/22280191}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 01,
volume = 2012,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2012},
month = {Sun Jan 01 00:00:00 EST 2012}
}