Collapse of Small-Scale Density Perturbations during Preheating in Single Field Inflation

  title={Collapse of Small-Scale Density Perturbations during Preheating in Single Field Inflation},
  author={Karsten Jedamzik and Martin Lemoine and J{\'e}r{\^o}me Martin},
  journal={Journal of Cosmology and Astroparticle Physics},
After cosmic inflation and before the transition to radiation domination, the cosmic energy density may have been dominated during an extended period by an oscillating massive scalar condensate. We show that during this period, sub-Hubble scale perturbations are subject to a metric preheating instability in the narrow resonance regime. We analyze in detail both, quadratic and quartic potentials. The instability leads to the growth of density perturbations which in many cases become non-linear… 

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