Does CAMB include the parameterisation (w0, wa) for the dark energy equation of state?

Use of Healpix, camb, CLASS, cosmomc, compilers, etc.
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Anais Rassat
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Does CAMB include the parameterisation (w0, wa) for the dark

Post by Anais Rassat » June 26 2008

Hi Everyone,

Does CAMB include the parameterisation (w0, wa) for the dark energy equation of state? It looks like the general code assumes w0 is a constant. There is a new 'quintessence' patch, but I can't figure out if this works for the (w0, wa) parameterisation (the link to the notes is broken).

Thanks, Anais.

Olga Mena
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Affiliation: IEEC Bellaterra Spain

Re: Does CAMB include the parameterisation (w0, wa) for the

Post by Olga Mena » June 26 2008

Hi Anais!

You can add the parametrization just by changing the equations.f90 file properly (do not forget to change the equations for the dark energy perturbations as well, since now the time derivative of w is not zero) and by adding the extra parameter wa in the params.ini file. You should also change the inidriver.f90 file, of course...

Let me know if that works!



Olga

Antony Lewis
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Re: Does CAMB include the parameterisation (w0, wa) for the

Post by Antony Lewis » June 26 2008

The notes are at

http://cosmologist.info/notes/CAMB.pdf

Of course if adding w_a you either need to restrict to models where w doesn't cross -1, or ignore problems that occur when it does.

Anais Rassat
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Joined: October 20 2004
Affiliation: LASTRO (EPFL)
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Re: Does CAMB include the parameterisation (w0, wa) for the

Post by Anais Rassat » June 26 2008

Thanks Olga and Antony. I'll have a look at this.

Savvas Nesseris
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Does CAMB include the parameterisation (w0, wa) for the dark

Post by Savvas Nesseris » June 27 2008

Also, you can have a look at the Mathematica Interface for CAMB, which allows for any 2 parameter w(z) equation of state, and can be found at (binaries, demo videos of the interface and documentation):

http://nesseris.physics.uoi.gr/

Cheers,
Savvas

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