Nonlinear power spectrum with varying equation of state of dark energy ?

[Pengyuan Gao]

Dear all,

I want to get the nonlinear power spectrum with varying equation of state of dark energy like w=w0+wa(1-a) .
But the halofit code are only for constant equation of state (although it can be differ from -1).

Can anyone tell me how to do that ,please?

Thanks a lot !

[Jason Dossett]

The latest version of CosmoMC and CAMB include a version of halofit for variable equation of state. CosmoMC is set to compile using that by default. In CAMB just make with the following command and you should be good to go:

Code: Select all

make NONLINEAR=halofit_ppf EQUATIONS=equations_ppf

[Pengyuan Gao]

Thanks Jason very much !
But I downloaded the latest CAMB and there is no a file named halofit_ppf.f90 . There is only halofit.f90 . Is it that I misunderstand your meaning?

Pengyuan

[Antony Lewis]

If you download CosmoMC, the version of CAMB included in the camb folder has the ppf versions.

[Pengyuan Gao]

In subroutine halofit in halofit_ppf.f90, about the last part of the fitting parameter a :
0.1749*om_v*(1.+w_lam)
I wonder whether w_lam should be changed to
w_lam+wa_ppf *(1-a) ? ( here 'a' is scale factor )

Because w is a function of redshift .

[Jason Dossett]

Hi Pengyuan,

Thanks very much for catching this. You are correct.

I am in the process of coding a fix.

-Jason