The thermodynamical evolution of the modified Chaplygin gas (MCG) with equation of state p = B ρ - A ρ- αis studied in the context of the Friedmann flat cosmological model. The temperature as a function of redshift z is obtained. In order to describe the universe since the radiation era, the constant B is chosen to be B = 1 / 3. Today's temperature of 2.7 K and the temperature at decoupling (z ≈ 1100) are used to fix the values of the parameters A and α, yielding α = 1 / 4 and A = (B + 1) ΩXρ0α + 1= (4 / 3) 0.7 ρ05 / 4. With these values, the redshift of the transition from positive to negative acceleration is calculated to be zc= 0.18. Using observational data for the redshift at over(a, ̈) = 0 and fixing B = 1 / 3, the best values for the other parameters are α = 1 / 4 and ΩX= 0.75, yielding T (z = 1100) ≈ 4000 K and zc= 0.25. © 2007 Elsevier B.V. All rights reserved.
Bedran, M. L., Soares, V., & Araújo, M. E. (2008). Temperature evolution of the FRW universe filled with modified Chaplygin gas. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 659(3), 462–465. https://doi.org/10.1016/j.physletb.2007.11.076