Inhomogeneous Primordial Nucleosynthesis: Coupled Nuclear Reactions and Hydrodynamic Dissipation Processes

We present a detailed numerical study of inhomogeneous Big Bang nucleosynthesis where, for the first time, nuclear reactions are coupled to all significant fluctuation dissipation processes. These processes include neutrino heat transport, baryon diffusion, photon diffusive heat transport, and hydrodynamic expansion with photon-electron Thomson drag. Light element abundance yields are presented for broad ranges of initial amplitudes and length scales for spherically condensed fluctuations. The H, He, He, and Li nucleosynthesis yields are found to be inconsistent with observationally inferred primordial abundances for all but very narrow ranges of fluctuation characteristics. Rapid hydrodynamic expansion of fluctuations late in the nucleosynthesis epoch results in significant destruction of Li (Be) only if the baryonic contribution to the closure density (Ωb) is less than or comparable to the upper limit on this quantity from homogeneous Big Bang nucleosynthesis. This implies that Li overproduction will preclude an increase on the upper limit for Ωb for any inhomogeneous nucleosynthesis scenario employing spherically condensed fluctuations. Subject headings: cosmology: early universe abundances, nuclear reactions, nucleosynthesis hydrodynamics