1303.3499 (Mark G. Jackson et al.)

Angular Correlation Functions for Models with Logarithmic Oscillations    [PDF]

Mark G. Jackson, Ben Wandelt, François Bouchet

There exist several theoretical motivations for primordial correlation functions (such as the power spectrum) to contain oscillations as a logarithmic function of comoving momentum k. While these features are commonly searched for in k-space, an alternative is to use angular space; that is, search for correlations between the directional vectors of observation. We develop tools to efficiently compute the angular correlations based on a stationary phase approximation and examine several example oscillations in the primordial power spectrum, bispectrum, and trispectrum. We find that logarithmically-periodic oscillations are essentially featureless and therefore difficult to detect using the standard correlator, though others might be feasible.

View original: http://arxiv.org/abs/1303.3499