Post-Born lensing

camb.postborn.get_field_rotation_BB(params, lmax=None, acc=1, CMB_unit='muK', raw_cl=False, spline=True)

Get the B-mode power spectrum from field post-born field rotation, based on perturbative and Limber approximations. See arXiv:1605.05662.

Parameters:

• params – model.CAMBparams instance with cosmological parameters etc.

• lmax – maximum \(\ell\)

• acc – accuracy

• CMB_unit – units for CMB output relative to dimensionless

• raw_cl – return \(C_\ell\) rather than \(\ell(\ell+1)C_\ell/2\pi\)

• spline – return InterpolatedUnivariateSpline, otherwise return tuple of lists of \(\ell\) and \(C_\ell\)

Returns:

InterpolatedUnivariateSpline (or arrays of sampled \(\ell\) and) \(\ell^2 C_\ell^{BB}/(2 \pi)\) (unless raw_cl, in which case just \(C_\ell^{BB}\))

camb.postborn.get_field_rotation_power(params, kmax=100, lmax=20000, non_linear=True, z_source=None, k_per_logint=None, acc=1, lsamp=None)

Get field rotation power spectrum, \(C_L^{\omega\omega}\), following arXiv:1605.05662. Uses the lowest Limber approximation.

Parameters:

• params – model.CAMBparams instance with cosmological parameters etc.

• kmax – maximum k (in \({\rm Mpc}^{-1}\) units)

• lmax – maximum L

• non_linear – include non-linear corrections

• z_source – redshift of source. If None, use peak of CMB visibility for CMB lensing

• k_per_logint – sampling to use in k

• acc – accuracy setting, increase to test stability

• lsamp – array of L values to compute output at. If not set, set to sampling good for interpolation

Returns:

\(L\), \(C_L^{\omega\omega}\): the L sample values and corresponding rotation power