Coupled Variations of Fundamental Couplings and Primordial Nucleosynthesis

11 pages, 6 figuresThe effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories. Considering only \he4, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. These constraints are then translated into constraints on the time variation of the Yukawa couplings and the fine structure constant. Furthermore, we show that a variation of the deuterium binding energy is able to reconcile the \li7 abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and \he4