Primordial nucleosynthesis with horizon-scale curvature fluctuations

We have used a plane-symmetric numerical relativity and hydrodynamics code to study the effect of horizon-scale inhomogeneities in the energy density and spacetime curvature on primordial nucleosynthesis. 2H, 3He, and 7Li yields are chiefly determined by the local baryon-to-photon ratios during nucleosynthesis, whereas 4He depends on previous dynamical history which determines how many neutrons survive until nucleosynthesis. Strong (δρ/ρ∼1) inhomogeneities are allowed by the observed abundances. Inhomogeneities usually raise both 4He and 2H but in some cases a nonadiabatic curvature inhomogeneity leads to a 4He yield below the standard-model result with the same average baryon-to-photon ratio