Stochastic quintessence models: Jerk and fine-structure variability constraints

• Published in: Physical review. D 2016-02, Vol.93 (4), Article 043509
• Main Authors: Dantas, Christine C., Ribeiro, André L. B.
• Format: Article
• Language: English
• Subjects: Constants; Cosmology; Coupling; Dark energy; Evolution; Mathematical models; Red shift; Stochasticity
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.93.043509

We report on constraints to the cosmological jerk parameter (j) and to possible variability of the fine-structure constant ( Delta alpha / alpha ) based on stochastic quintessence models of dark energy, discussed by Chongchitnan and Efstathiou [Phys. Rev. D 76, 043508 (2007)]. We confirm the results by these authors in the sense that many viable solutions can be obtained, obeying current observational constraints in low redshifts. We add the observables j and Delta alpha / alpha to this conclusion. However, we find peculiarities that may produce, in the nearby universe, potential observational imprints in future cosmological data. We conclude, for redshifts z[< or =]3, that (i) j(z) fluctuates due to the stochasticity of the models, reaching an amplitude of up to 5% relatively to the [Lambda] cold dark matter model value (j sub([Lambda]CDM)=1); and (ii) by contrasting two distinct ("extreme") types of solutions, variabilities in alpha (z), linked to a linear coupling ([zeta]) between the dark energy and electromagnetic sectors, are weakly dependent on redshift, for couplings of the order [zeta]~10 super(-4), even for large variations in the equation of state parameter at relatively low redshifts. Nonlinear couplings produce an earlier and steeper onset of the evolution in Delta alpha / alpha (z), but can still accommodate the data for weak enough couplings.