Primordial Black Holes from Sound Speed Resonance during Inflation

May 9, 2018
6 pages
Published in:
  • Phys.Rev.Lett. 121 (2018) 8, 081306
  • Published: Aug 24, 2018
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Abstract: (APS)
We report on a novel phenomenon of the resonance effect of primordial density perturbations arisen from a sound speed parameter with an oscillatory behavior, which can generically lead to the formation of primordial black holes in the early Universe. For a general inflaton field, it can seed primordial density fluctuations, and their propagation is governed by a parameter of sound speed square. Once, if this parameter achieves an oscillatory feature for a while during inflation, a significant nonperturbative resonance effect on the inflaton field fluctuations takes place around a critical length scale, which results in significant peaks in the primordial power spectrum. By virtue of this robust mechanism, primordial black holes with specific mass function can be produced with a sufficient abundance for dark matter in sizable parameter ranges.
Note:
  • 6 pages, 4 figures; v2: figures replotted with corrections, analysis extended, version accepted by Phys.Rev.Lett
  • Gravitation and Astrophysics
  • black hole: primordial
  • velocity: acoustic
  • density: primordial
  • resonance: effect
  • power spectrum: primordial
  • density: fluctuation
  • density: perturbation
  • inflation: model
  • inflaton