Revisiting Primordial Nucleosynthesis: Implications For Light Element Abundances in Alternative Cosmological Models

Primordial nucleosynthesis is one of the key pillars of the Big Bang theory, successfully predicting the relative abundances of light elements such as hydrogen, helium, and lithium. However, discrepancies between predicted and observed lithium abundances (the "lithium problem") have persisted, prompting investigations into alternative cosmological models. This paper explores the implications of varying the conditions of early-universe expansion, baryon density, and neutrino decoupling in non-standard Big Bang scenarios. Using modified cosmological parameters, we analyze their effects on primordial nucleosynthesis through simulations, offering potential resolutions to the lithium problem while preserving the success of hydrogen and helium predictions.