Integrating Friedmann Equation of Multi-component universe respect to a and t

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SUMMARY

The discussion focuses on integrating the Friedmann equation in a multi-component universe, specifically for matter-curvature and matter-lambda scenarios. The integrals presented are: for matter-curvature only, H_0 t = ∫_0^a (da/[Ω_0/a + (1-Ω_0)]^{1/2}), and for matter-lambda only, H_0 t = ∫_0^a (da/[Ω_0/a + (1-Ω_0)a^2]^{1/2}). The solution for the matter-lambda case is derived as a(t) = (ρ_matter/ρ_lambda)^(1/3) * [sinh[(6πρ_lambdaG)^(1/2)t]^(2/3). This provides a clear relationship between scale factor 'a' and time 't' in cosmological models.

PREREQUISITES
  • Understanding of Friedmann equations in cosmology
  • Familiarity with integrals and calculus
  • Knowledge of matter-energy density parameters (Ω_0)
  • Basic concepts of cosmological models (matter-curvature and matter-lambda)
NEXT STEPS
  • Study the derivation of the Friedmann equations in detail
  • Explore the implications of different density parameters on cosmic evolution
  • Learn about the role of dark energy in the matter-lambda universe
  • Investigate numerical methods for solving integrals in cosmology
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Astronomers, cosmologists, and physics students interested in the dynamics of the universe and the mathematical relationships governing cosmic expansion.

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I am having a trouble finding relationship between 'a' and 't' by integrating friedmann equation in a multi-component universe.

It would be very helpful if you can help me with just
matter-curvature only universe and matter-lambda only universe.

The two integrals looks like following.

Matter-curvature only:

H_0 t = ∫_0^a \frac{da}{[Ω_0/a + (1-Ω_0)]^{1/2}}

Matter-Lambda only:

H_0 t = ∫_0^a \frac{da}{[Ω_0/a + (1-Ω_0)a^2]^{1/2}}

Thank you for your help.
 
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Try substituting x = 1/a and then use a table of integrals.
 
with matter lambda the result is
a(t)=(ro_matter/ro_lambda)^(1/3)*[sinh[(6*Pi*ro_lambda*G)^(1/2)*t]^(2/3)
Where ro_x/ro_critical=omega_0x
 

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