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I try to understand power spectra for large scale structure and CMB analyses for my exams.

I constantly find the expression for linear power spectra [itex]P(k) = A\cdot k^{n_s}\cdot T^2(k)[/itex]. I understand that this comes from primodial primodial fluctuations and the tranfer function kind of "evolves" the spectrum to our time.

What I don't understand is the following: Why does the BAO make wiggles? I the correlation function there is only one bump from BAO, as much as I know.

What is the nonlinear power spectrum? Why are the wiggles removed from the plots sometimes in the analyses?

Thank you

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# Linear Power Spectrum

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