Abstract
AbstractWe present an explicit detailed theoretical and observational investigation of an anisotropic massive Brans–Dicke (BD) gravity extension of the standard $$\Lambda $$ΛCDM model, wherein the extension is characterized by two additional degrees of freedom; the BD parameter, $$\omega $$ω, and the present day density parameter corresponding to the shear scalar, $$\Omega _{\sigma ^2,0}$$Ωσ2,0. The BD parameter, determining the deviation from general relativity (GR), by alone characterizes both the dynamics of the effective dark energy (DE) and the redshift dependence of the shear scalar. These two affect each other depending on $$\omega $$ω, namely, the shear scalar contributes to the dynamics of the effective DE, and its anisotropic stress – which does not exist in scalar field models of DE within GR – controls the dynamics of the shear scalar deviating from the usual $$\propto (1+z)^6$$∝(1+z)6 form in GR. We mainly confine the current work to non-negative $$\omega $$ω values as it is the right sign – theoretically and observationally – for investigating the model as a correction to the $$\Lambda $$ΛCDM. By considering the current cosmological observations, we find that $$\omega \gtrsim 250$$ω≳250, $$\Omega _{\sigma ^2,0}\lesssim 10^{-23}$$Ωσ2,0≲10-23 and the contribution of the anisotropy of the effective DE to this value is insignificant. We conclude that the simplest anisotropic massive BD gravity extension of the standard $$\Lambda $$ΛCDM model exhibits no significant deviations from it all the way to the Big Bang Nucleosynthesis. We also point out the interesting features of the model in the case of negative $$\omega $$ω values; for instance, the constraints on $$\Omega _{\sigma ^2,0}$$Ωσ2,0 could be relaxed considerably, the values of $$\omega \sim -1$$ω∼-1 (relevant to string theories) predict dramatically different dynamics for the expansion anisotropy.
Publisher
Springer Science and Business Media LLC
Subject
Physics and Astronomy (miscellaneous),Engineering (miscellaneous)
Reference165 articles.
1. A.A. Starobinsky, A new type of isotropic cosmological models without singularity. Phys. Lett. B 91, 99 (1980)
2. A.A. Starobinsky, A new type of isotropic cosmological models without singularity. Adv. Ser. Astrophys. Cosmol. 3, 130 (1987)
3. A.H. Guth, The inflationary universe: a possible solution to the horizon and flatness problems. Phys. Rev. D 23, 347 (1981)
4. A.H. Guth, The inflationary universe: a possible solution to the horizon and flatness problems. Adv. Ser. Astrophys. Cosmol. 3, 139 (1987)
5. A.D. Linde, A new inflationary universe scenario: a possible solution of the horizon, flatness, homogeneity, isotropy and primordial monopole problems. Phys. Lett. B 108, 389 (1982)
Cited by
20 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献