Stochastic Isocurvature Baryon Fluctuations, Baryon Diffusion, and Primordial Nucleosynthesis

摘要

We examine effects on primordial nucleosynthesis from a truly random, one-dimensional spatial distri- ution in the baryon-to-photon ratio (η). We generate stochastic fluctuation spectra characterized by different spectral indices and rms fluctuation amplitudes. For the first time we explicitly calculate the effects of baryon diffusion on the nucleosynthesis yields of such stochastic fluctuations. We also consider the collapse instability of large mass scale inhomogeneities. Our results are generally applicable to any primordial mechanism producing fluctuations in ηwhich can be characterized by a spectral index. In particular, these results apply to primordial isocurvature baryon fluctuation (PIB) models