Unit transformation of Cosmological Constant ?

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Discussion Overview

The discussion revolves around the unit transformation of the cosmological constant, specifically converting values between GeV and eV, as well as comparing energy densities in different units. The scope includes theoretical aspects of cosmology and mathematical reasoning related to unit conversions.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • The original poster seeks clarification on how to convert the cosmological constant from GeV4 to eV and vice versa, as well as comparing energy densities.
  • One participant suggests that the conversions are useful for cosmology equations, providing specific conversion factors for temperature, mass, time, and length related to GeV.
  • Another participant points out that eV is a unit of energy, while energy densities have dimensions of energy/length3, which can be related to energy4 under certain unit conventions.
  • The original poster expresses gratitude for the explanation and invites further contributions from others.

Areas of Agreement / Disagreement

Participants generally agree on the need for unit conversions in cosmology, but there is no consensus on the specific methods or implications of these transformations, particularly regarding the comparison of energy and energy density.

Contextual Notes

The discussion includes assumptions about unit conventions, such as setting c=hbar=1, which may not be universally accepted. There are also unresolved aspects regarding the implications of these conversions for cosmological models.

Who May Find This Useful

Individuals interested in cosmology, theoretical physics, and those working with unit conversions in energy-related contexts may find this discussion relevant.

icarus2
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Question : How to unit transformation of Cosmological Constant?

10-47 GeV4 ===> ? eV
or, x eV ===> ? GeV4


1) How compair ( X ) GeV4 with ( Y ) eV ?

2) How compair ( 10-29 g/cm3) with (Y eV)?

please, easely explain to me!
and, have a nice day!
 
Last edited:
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Try these conversions. They are a good tool when working with cosmology equations like scalar field inflation models.

Temperature: 1 GeV ---> 10^13 K
Mass: 1 GeV ---> 10^-25 g
Time: 1 GeV^-1 ---> 10^-24 sec
Length: 1 GeV^-1 ---> 10^-14 cm
 
Thanks you!
I will try by them.

If reader have a better idea, please write down!
 
You are comparing energies with energydensities. eV is of dimension energy.
But if c=hbar=1 (cosmologists tend to redefine their units like that), length and time have the same dimension, that is they are both of dimension energy^-1.

Thus, energy densities (energy/Length^3) have the same dimension as energy^4.
 
Thanks Amanheis! good explain!

I have make a challenge to that fine tuning problem(the reason of that mass density of universe close to critical mass density), inflation mechanism(start and end), the reason of that dark energy has a small value, future of our universe, at Physics Forums Blog.
 
Last edited:
edgepflow said:
Try these conversions. They are a good tool when working with cosmology equations like scalar field inflation models.

Temperature: 1 GeV ---> 10^13 K
Mass: 1 GeV ---> 10^-25 g
Time: 1 GeV^-1 ---> 10^-24 sec
Length: 1 GeV^-1 ---> 10^-14 cm

I got a solution
 
Last edited:

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