Abstract
A generalized dynamical equation for the scale factor of the universe is proposed to describe the cosmological evolution, of which the ΛCDM model is a special case. It also provides a general example to show the equivalence of the modified equation of state (EOS) and a scalar field model. In the mathematical aspect, the EOS, the scalar field potential V(φ), and the scale factor a(t) all have possessed analytical solutions. Such features are due to a simple form invariance of the equation inherited which determines the Hubble parameter. From the physical point of view, this dynamical equation can be regarded as the ΛCDM model with bulk viscosity, an existence content in the universe. We employ the SNe Ia data with the parameter A measured from the SDSS data and the shift parameter R measured from WMAP data to constrain the parameters in our model. The result is that the contribution of the bulk viscosity, accumulated as an effective dark energy responsible for the current cosmic accelerating expansion, is made approximately ten percent to that of the cosmological constant.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
