Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion

In this talk, I will present recent developments in perturbation theory regarding the study of the large-scale clustering of galaxies in theories with scale-dependent linear growth, such as those involving massive neutrinos and modified gravity. The challenge in these models is that the introduced scale is incorporated into the perturbative kernels. We utilize the Lagrangian approach to compute these kernels and then map them to the Eulerian frame to obtain the power spectrum. Unfortunately, our method for computing statistics is quite slow. Therefore, we simplify the modified kernels by retaining only the terms that contain the scale-dependent growth factor. By doing so, we can use FFTLog techniques to calculate loop integrals at a speed similar to that of the standard LCDM model. This approach enables us to estimate parameters from BOSS and eBOSS data using standard MCMC methods.