Nov 1, 2018 - Check kappa power spectra

As a sanity check we compare power spectra of the kappa maps from George's sims against theoretical expectations from CAMB. The dictionary between the two languages is

[math]\displaystyle{ \phi_{\ell m} = \frac{2\kappa_{\ell m}}{\ell(\ell+1)} }[/math]

The CAMBdemo code from https://camb.readthedocs.io/en/latest/CAMBdemo.html contains an analytic code based on Limber approximation to calculate power spectrum of the CMB lensing potential. We slightly modify it to be applicable to our case of a general comoving distance. In the plots below we compare power spectra from the Peak Patch simulations against analytic expectation based on (non)linear matter power spectrum. Just for a quick check we also plot CMB lensing potential power spectrum, both from full CAMB and from the analytic expectation.