CAMB Quintessence perturbations

Use of Cobaya. camb, CLASS, cosmomc, compilers, etc.
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Martina Schwind
Posts: 30
Joined: March 11 2013
Affiliation: University Heidelberg

CAMB Quintessence perturbations

Post by Martina Schwind » January 21 2014

Dear Anthony,

I want to change the perturbations of the scalar field coupled to mass varying neutrinos according to the paper:
http://arxiv.org/pdf/astro-ph/0512367v3.pdf

Right now I am not clear about what Your perturbation variable for the field is, where there is a "delta_phi".

Is the perturbation equation related to the Klein-Gordon equation?
If yes: how to I come from the Klein-Gordon equation to Your perturbation of the scalar field.

I would be really happy for any help,

Martina

Antony Lewis
Posts: 1941
Joined: September 23 2004
Affiliation: University of Sussex
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Re: CAMB Quintessence perturbations

Post by Antony Lewis » January 21 2014

In equations_quint.f90 for quintessence, the perturbation variable is clxq (and vq for its derivative)

Martina Schwind
Posts: 30
Joined: March 11 2013
Affiliation: University Heidelberg

CAMB Quintessence perturbations

Post by Martina Schwind » January 21 2014

Thanks!
This I know, but why do You use the derivative of phi as a perturbation variable and not delta_phi? This confuses me...

Martina Schwind
Posts: 30
Joined: March 11 2013
Affiliation: University Heidelberg

CAMB Quintessence perturbations

Post by Martina Schwind » January 21 2014

ok, what I see right now:
when You have a delta_psi You have a spatial derivative as well.
So are You perturbing in:
psi + SD_a psi ?

this sounds good the longer I think about it...

Martina Schwind
Posts: 30
Joined: March 11 2013
Affiliation: University Heidelberg

CAMB Quintessence perturbations

Post by Martina Schwind » January 22 2014

Right now I read chapter 6 of Your thesis.
I have some questions:
- in chapter 6.9 Your describe the single-field inflation and it seems to me that this is the same as for the quintessence model of Your CAMB notes of Okt. 2013, is this right?
- how do I fix to the zero-acceleration frame (the CDM frame)?
- how do I get this equation (6.94) of Your thesis?

Is there a possibility to read this somewhere else?

Gansukh Tumurtushaa
Posts: 34
Joined: October 05 2013
Affiliation: Sogang univ.

CAMB Quintessence perturbations

Post by Gansukh Tumurtushaa » January 23 2014

Hi?

where can one get the thesis that you just mentioned?

-Gansukh

Martina Schwind
Posts: 30
Joined: March 11 2013
Affiliation: University Heidelberg

CAMB Quintessence perturbations

Post by Martina Schwind » January 23 2014

at his homepage:
http://cosmologist.info/
in the almost very end on the right:
"download a Postscript copy."

Antony Lewis
Posts: 1941
Joined: September 23 2004
Affiliation: University of Sussex
Contact:

Re: CAMB Quintessence perturbations

Post by Antony Lewis » January 23 2014

There must be much better (and prior) references than my thesis!

There may be some useful references in astro-ph/0307104. In my notation the CDM frame corresponding to setting the acceleration A=0. The CAMB notes also has some relevant description for CAMB.

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