New Approaches to Cosmology: Bridging Simulations and Observations

New methodologies in cosmology are emerging, particularly in bridging simulations and observational data to enhance our understanding of cosmic structures. A notable advancement is the hybrid effective field theory (HEFT) forward model presented in a recent study, which focuses on the Lyman-alpha forest.

This model utilizes non-linear particle displacements from the AbacusSummit simulation suite combined with an analytical, perturbative bias forward model, achieving a 5 percent accuracy level in power spectra modeling.

Another innovative approach involves the $ ext{Z}$-$ ext{kappa}$ transform, which effectively reveals primordial information in large-scale structure by Gaussianizing the density distribution through local nonlinear transformations.

This method demonstrates strong complementary constraints on parameters like primordial non-Gaussianity and is set to aid Stage-IV surveys in probing early Universe physics. Such advancements indicate a substantial shift toward more robust and interpretable cosmological models, which are crucial for future research, especially with instruments like the Dark Energy Spectroscopic Instrument (DESI) and its successor, DESI-II.