Perturbation theory trispectrum in the time renormalization approach

An accurate theoretical description of structure formation at least in the mildly non-linear regime is essential for comparison with data from next-generation galaxy surveys. In a recent approach, one follows the time evolution of correlators directly and finds a hierarchy of evolution equations with increasing order. So far, in this so-called time renormalization group method, the trispectrum was neglected in order to obtain a closed set of equations. In this work, we study the influence of the trispectrum on the evolution of the power spectrum. In order to keep the numerical cost at a manageable level, we use the tree-level trispectrum from Eulerian perturbation theory. In comparison to numerical simulations, we find improvement in the mildly non-linear regime up to k similar or equal to 0.25 h Mpc(-1). Beyond k similar or equal to 0.25 h Mpc(-1) the perturbative description of the trispectrum fails and the method performs worse than without the trispectrum included. Our results reinforce the conceptual advantage of the time renormalization group method with respect to the perturbation theory.