Higgs inflation
[1] is based on the idea of non-minimaly coupled inflation. It allows for inflation by a small modification of the
Standard Model, which does not introduce new degrees of freedom, and modifies the physics at low (available in laboratory experiments) energies very weakly.
The only modification of the
Standard Model action consist of introduction of non-minimal coupling of the
Higgs field to gravity
where
is the Ricci scalar and
is the
Higgs field. Note, that in principle this term is required by the renormalizability of the theory in curved space-time.
This term is equivalent to effectively flattening the Higgs potential at large field values, allowing for generation of primordial density perturbations with observed amplitude. This requires a rather large
, where
is the Higgs boson self coupling constant.
It predicts definite value for the spectral index
and very weak tensor perturbations,
.
It relies also on absence of other new physics up to the Planck scale.
References:- [1]^ F. L. Bezrukov and M. Shaposhnikov, ``The Standard Model Higgs boson as the inflaton,'' Phys. Lett. B 659 (2008) 703 [arXiv:0710.3755 [hep-th]].