STOLAS: STOchastic LAttice Simulation

概要

Cosmic inflation is known to address problems in the Big Bang theory and to generate the fluctuations that seed the current cosmological structures. Its existence is strongly suggested by the Planck observation of the cosmic microwave background (CMB). Though the CMB observation implies small fluctuations on large scales, large fluctuations may be realized on a smaller scale and the primordial black holes (PBHs) may be made by their gravitational collapse. PBHs have gotten much attention lately as candidates for dark matter and may be searched for by LISA in future probes. However, the detailed analysis of the PBH formation from inflation requires a lot of assumptions, particularly in the statistics of the primordial curvature perturbations.

In this talk, I introduce a numerical lattice simulation of inflation in the stochastic approach (STOLAS: STOchastic LAttice Simulation). It enables us to know the true statistics of the curvature perturbation and predict the accurate statistic of PBH in each inflation model.

I show examples in some models. I also describe the importance sampling technique to sample efficiently the large perturbation related to PBH formation.

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