https://doi.org/10.1140/epjc/s10052-020-8199-9
Regular Article - Theoretical Physics
Barotropic fluid compatible parametrizations of dark energy
1
University of Applied Health Sciences, Mlinarska street 38, 10000, Zagreb, Croatia
2
Catholic University of Croatia, Ilica 242, 10000, Zagreb, Croatia
* e-mail: hrvoje.stefancic@unicath.hr
Received:
9
May
2020
Accepted:
3
July
2020
Published online:
16
July
2020
Parametrizations of equation of state parameter as a function of the scale factor or redshift are frequently used in dark energy modeling. The question investigated in this paper is if parametrizations proposed in the literature are compatible with the dark energy being a barotropic fluid. The test of this compatibility is based on the functional form of the speed of sound squared, which for barotropic fluid dark energy follows directly from the function for the Equation of state parameter. The requirement that the speed of sound squared should be between 0 and speed of light squared provides constraints on model parameters using analytical and numerical methods. It is found that this fundamental requirement eliminates a large number of parametrizations as barotropic fluid dark energy models and puts strong constraints on parameters of other dark energy parametrizations.
© The Author(s), 2020
