Classical stochastic approach to cosmology revisited

Pramana

K Babu Joseph¹  Moncy V John1 2¹  C Sivakumar1¹ 

[1] Department of Physics, Cochin University of Science and Technology, Kochi 682 022, India$$

关键词: Cosmology;    Hubble parameter;    Fokker–Planck equation;    supernovae data.;   

DOI  :  

学科分类：物理（综合）

来源: Indian Academy of Sciences

【 摘 要 】

The classical stochastic model of cosmology recently developed by us is reconsidered. In that approach the parameter 𝑤 defined by the equation of state 𝑝 = wρ was taken to be fluctuating with mean zero and we compared the theoretical probability distribution function (PDF) for the Hubble parameter with observational data corresponding to a universe with matter and vacuum energy. Even though qualitative agreement between the two was obtained, an attempt is herein made to introduce a more realistic assumption for the mean ofwand use it for the calculations. In the present theory the mean values of both 𝑝 and 𝑤 are taken to be nonzero. The theoretical and observational PDFs are compared for different epochs and values of the Hubble parameter. The corresponding values of the diffusion constant 𝐷 obtained are approximately constant. We use the scatter in the observed redshift-magnitude data of Type Ia supernova to place limits on the stochastic variation in expansion rate and consequently, on the stochastic variation of the equation of state.

【 授权许可】

Unknown