define different spectral index for isocurvature

[sthagstotz]

Dear all, I'm playing around with some models that include isocurvature and a different spectral index for the corresponding power spectrum, n_cdi != n_s. I found that there is a line in data.py that enforces n_s = n_cdi even if both are defined (and supposed to be varied) separately:

            elif elem == 'f_cdi':                                                                                                
                self.cosmo_arguments['n_cdi'] = self.cosmo_arguments['n_s']     

is there a reason for this behaviour? Or should it be removed?

Best Steffen

[brinckmann]

Hi Steffen,

I hope you're doing well!

I have never worked on isocurvature, but it seems to me if you're fixing or varying the entropy-to-curvature ratio f_cdi and you're considering a case where the cold dark matter isocurvature tilt is not the same as the primoridial power spectrum tilt, n_cdi != n_s, that you would want to comment those two lines. I suspect that it's in there from a time when someone was considering a case where n_cdi = n_s was always true. These additions sometimes slip in there, so it's a good thing you caught it!

Best, Thejs