Primordial black holes and scalar induced secondary gravitational waves from Higgs inflation with non-canonical kinetic term.

By combining the noncanonical kinetic term with the nonminimal coupling between gravity and Higgs field, we propose a novel inflationary mechanism and show that the curvature perturbation at small scales can be enhanced by the fluctuations of the Higgs field while satisfying the cosmic microwave background observations at large scales. We find that the recent NANOGrav signal and the black holes in LIGO-Virgo events may originate from the vacuum fluctuations of Higgs field. The cosmological probe of Higgs field by space-based gravitational wave observatory in the future is proposed. We also consider the non-Gaussianity effect on the abundance of primordial black holes and scalar induced secondary gravitational waves. We find that primordial non-Gaussianity makes primordial black holes form more easily, but its effect on the energy density of scalar induced gravitational waves is negligible.