Matter bispectrum beyond Horndeski
Abstract
The Horndeski scalar-tensor theory and its recent extensions allow nonlinear derivative interactions of the scalar degree of freedom. We study the matter bispectrum of large scale structure as a probe of these modified gravity theories, focusing in particular on the effect of the terms that newly appear in the so-called "beyond Horndeski" theories. We derive the second-order solution for the matter density perturbations and find that the interactions beyond Horndeski lead to a new time-dependent coefficient in the second-order kernel which differs in general from the standard value of general relativity and the Horndeski theory. This can deform the matter bispectrum at the folded triangle configurations (), while it is never possible within the Horndeski theory.
Cite
@article{arxiv.1801.07885,
title = {Matter bispectrum beyond Horndeski},
author = {Shin'ichi Hirano and Tsutomu Kobayashi and Hiroyuki Tashiro and Shuichiro Yokoyama},
journal= {arXiv preprint arXiv:1801.07885},
year = {2018}
}
Comments
12 pages, 4 figures