Why include -xi*H in the equation of state?

AI Thread Summary
The discussion centers on the inclusion of the term -xi*H in the equation of state for a perfect fluid, which is typically expressed as p=w*rho. The term -xi*H is introduced to analyze the dynamics of the system, specifically focusing on the time evolution of density (rho) and the Hubble parameter (H). The relevance of this term lies in its utility for examining the equations for the time derivatives of density and Hubble parameter, allowing for a more comprehensive understanding of the cosmological dynamics. The conversation emphasizes that this inclusion is not about modifying the cosmological constant but rather about solving the dynamical system for rho and H. Ultimately, the term enhances the analysis of cosmological behavior in the context of single fluid cosmology.
odd-socks
Messages
2
Reaction score
0
I'm aware that the equation of state for a perfect fluid (when considering single fluid cosmology) is p=w*rho

However I've come across an equation of state of p=w*rho - xi*H, H being Hubble's parameter. However I cannot find an explanation of why you can put this in? Can anyone explain this to me please?

Thanks
 
Space news on Phys.org
It is irrelevant. You wish to inject it into the cosmological constant?
 
its to look at equations for rhodot (d rho/dt) and Hdot (dH/dt) so solve as a dynamical system for rho and H
 

Thread 'Questions about quantum cosmology'

what is the current status of the field for quantum cosmology, are there any observations that support any theory of quantum cosmology? is it just cosmology during the Planck era or does it extend past the Planck era. what are the leading candidates into research into quantum cosmology and which physics departments research it? how much respect does loop quantum cosmology has compared to string cosmology with actual cosmologists?
View full post »

Similar threads

A Equation of State w=1: Why Not Considered in Cosmology?
Replies
4
Views
2K
I Can a scalar field model account for the cosmic redshift?
Replies
20
Views
2K
  • Sticky
Insights Equations of State for Photon Gas and Relativistic Electron Gas
Replies
0
Views
6K
A Anisotropic Universe and Friedmann Equations
Replies
27
Views
5K
A Does the Hadronic Era Alter the Equation of State?
Replies
12
Views
2K
3 fates of universe holds for which cosmological fluids?
Replies
3
Views
1K
I Questions about Negative Pressure and Vacuum Energy
Replies
5
Views
3K
I Meaning of the inertial energy density
Replies
1
Views
1K
A Why are the Navier-Stokes equations inconsistent in this case?
Replies
18
Views
2K
Chemistry What is "gauge pressure" and how does a manometer work?
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top