Examples

Parametrizations implemented in MGCAMB
New parametrizations in 2015 version
We added new models basing on the parametrization of screened scalar tensor theories introduced in arXiv:1203.4812. They are parametrized through the m, beta parametrization. It is possible to introduce this new parametrization using the following relations which link the (m(a), β(a)) parametrization with the (μ(a,k), γ(a,k)) parametrization used in the previous version of MGCAMB (2013 version)

  • Symmetron model implemented through the following parametrization and denoted in the code as model 7,

    In the plots above the parameters used are:



  • Generalized Dilaton model implemented through the following parametrization and denoted in the code as model 8,

    In the plots above the parameters used are:



  • Hu-Sawicki f(R) gravity introduced in arXiv:0705.1158. This model is introduced using the following parametrization and denoted in the code as model 9,

    In the plots above the parameters used are:



  • Dilaton model introduced through the following parametrization and denoted in the code as model 10,

    In the plots above the parameters used are:



Original parametrizations implemented in MGCAMB
The following models are introduced by parametrizing directly the μ and γ functions.

  • f(R): Setting β1 = 4/3, λ22 = β1 λ12 and β2 = 1/2 and

    where λ12 = B0 c2 /(2H0 ) would describe f(R) models for B0 < 1 as explained in arXiv:0909.2045.


  • Chameleon (Yukawa-type dark matter interaction): It is an extension to Chameleon models introduced above. Setting λ22 = β1 λ12 , β2 = 2/β1 -1 with 0 < B0 < 1, 0 < β1 < 2 and 1 < s < 4 gives the chameleon models considered in arXiv:0909.2045.



  • Bean and Tangmatitham parametrization arXiv:1002.4197: The parametrization is

    where for late times, when anisotropic stress is small, we have




  • Linder's γ parametrization ( γL): This is a commonly used parameter defined as arXiv:0701317





    where the scale dependence is neglected.