Successful Higgs inflation from combined nonminimal and derivative
  couplings
  We propose an inflationary scenario based on the concurrent presence of
non-minimal coupling (NMC) and generalized non-minimal derivative coupling
(GNMDC), in the context of Higgs inflation. The combined construction maintains
the advantages of the individual scenarios without sharing their disadvantages.
In particular, a long inflationary phase can be easily achieved due to the
gravitational friction effect owed to the GNMDC, without leading to
trans-Planckian values and unitarity violation. Additionally, the
tensor-to-scalar ratio remains to low values due to the NMC contribution.
Finally, the instabilities related to the squared sound-speed of scalar
perturbations, which plague the simple GNMDC scenarios, are now healed due to
the domination of the NMC contribution and the damping of the GNMDC effects
during the reheating era. These features make scenarios with nonminimal and
derivative couplings to gravity successful candidates for the description of
inflation.
