Probing new physics with multi-vacua quantum tunnelings beyond standard
  model through gravitational waves
  We report on a novel phenomenon of particle cosmology, which features
specific cosmological phase transitions via quantum tunnelings through multiple
vacua. The latter is inspired by the axiverse ideas and enables us to probe the
associated new physics models through a potential observation of specific
patterns in the stochastic gravitational waves background. Multiple vacua may
induce the nucleation of co-existing bubbles over the phase transition epoch,
hence enhancing the overall process of bubbles' nucleation. Our detailed
analysis of semi-analytical and numerical solutions to the bounce equations of
the path integral in three vacua case has enabled us to determine the existence
of three instanton solutions. This new mechanism of cosmological phase
transitions clearly predicts a possibly sizeable new source of gravitational
waves, with its energy spectrum being featured with particular patterns, which
could be probed by the future gravitational wave interferometers.
