A full simulations pipeline for Coupled Dark Energy models with PANDA-Gadget4

The ΛCDM model provides a successful framework for modern cosmology but faces increasing tension with recent high-precision observations, particularly in the values of the Hubble constant H0, the growth of structure parameter S8, and the dark energy equation-of-state parameter w. These discrepancies motivate the investigation of alternative cosmological scenarios. In this work, we study a class of Coupled Dark Energy models known as Bouncing Coupled Dark Energy (BCDE), where the DE component is described by a scalar field interacting with other species and evolving under a confining potential. These models present a peculiar dynamic represented by a bouncing point where the field stops and reverses direction. This dynamic can suppress late-time structure growth and potentially alleviate current observational tensions. To explore BCDE cosmologies in the non-linear regime, we develop a comprehensive simulation pipeline. We developed and implemented a new version of the PANDA-Gadget4 N-body code that captures the main physical features of BCDE models: time-dependent particle masses, a velocity-dependent friction term, and a fifth force enhancing gravitational interactions. This implementation not only enables simulations of BCDE scenarios but also lays the groundwork for exploring a broader class of Interacting Dark Energy (IDE) models. We complement this with the DORIAN Python library, developed to analyze lightcone outputs from Gadget4 and extract weak lensing observables. Our results highlight the distinct signatures of BCDE models in the matter power spectrum, halo mass function, and weak lensing signals, offering testable predictions for future observational surveys. This pipeline, from theoretical analysis of dark energy models to their non-linear evolution with our implementation in PANDA-Gadget and observational signatures in weak lensing with DORIAN, provides a robust toolset to test and constrain coupled dark energy scenarios with upcoming cosmological data.