In the non-relativistic regime, pertinent to the large scale structure of the Universe, the leading effect of a long-wavelength perturbation δ(λL) on short distance physics is a uniform acceleration ∝λLδ(λL). Typically, this has no effect on statistical averages at equal time since a uniform acceleration results in a uniform translation -- a reasoning that has been formalized as a "consistency condition" on the cosmological correlation functions. This naive expectation fails in the presence of the baryon acoustic feature provided λL<ℓBAO. We derive the squeezed limit of correlation functions in this regime.
@article{arxiv.1412.3796,
title = {Baryon Acoustic Peak and the Squeezed Limit Bispectrum},
author = {Mehrdad Mirbabayi and Marko Simonović and Matias Zaldarriaga},
journal= {arXiv preprint arXiv:1412.3796},
year = {2015}
}