CAMB: How to define pivot scalar for set_initial_power_table()?

Use of Cobaya. camb, CLASS, cosmomc, compilers, etc.
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John Wick
Posts: 3
Joined: April 28 2023
Affiliation: Louisiana State University

CAMB: How to define pivot scalar for set_initial_power_table()?

Post by John Wick »

I want to calculate the angular power spectrum for a power spectrum which is normalized at k_pivot = 10 not k = 0.05 which is the case for Planck data. I used set_initial_power_table() function but since the power spectrum is normalized at k=10 not k=0.05 I cannot get a correct angular power since the power spectrum is larger in k=0.05 and is not scale invariant. How can I set the pivot scale for customized power spectrum for arbitrary pivot scale?
Antony Lewis
Posts: 1961
Joined: September 23 2004
Affiliation: University of Sussex
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Re: CAMB: How to define pivot scalar for set_initial_power_table()?

Post by Antony Lewis »

If you are using set_initial_power_table to set your on power spectrum, it's up to you to normalize it how you like.

For the default power law spectrum you can use the pivot_scalar parameter.
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