The accelerated expansion of space during the cosmological inflation period leads to trans-
Planckian issues which need to be addressed. Most importantly, the physical wavelength of …

I argue that cosmological data from the epoch of primordial inflation is catalyzing the
maturation of quantum gravity from speculation into a hard science. I explain why quantum …

A bstract Perturbative quantum corrections to primordial power spectra are important for
testing the robustness and the regime of validity of inflation as an effective field theory …

A bstract We consider two nonlinear sigma models on de Sitter background which involve
the same derivative interactions as quantum gravity but without the gauge issue. The first …

We study the power spectrum of super-Hubble fluctuations of an inflatonlike scalar field, the
“system,” coupled to another scalar field, the “environment” during de Sitter inflation. We …

A bstract In this paper, we prove that the superhorizon conservation of the curvature
perturbation ζ in single-field inflation holds as an operator statement. This implies that all ζ …

A bstract Studying loop corrections to inflationary perturbations, with particular emphasis on
infrared factors, is important to understand the consistency of the inflationary theory, its …

The conventional cosmological perturbation theory has been performed under the
assumption that we know the whole spatial region of the universe with infinite volume. This …

A bstract We calculate 1-loop corrections to the Schwinger-Keldysh propagators of Standard-
Model-like fields of spin-0, 1/2, and 1, with all renormalizable interactions during inflation …

We obtain the nonequilibrium effective action of an inflatonlike scalar field—the system—by
tracing over sub-Hubble degrees of freedom of “environmental” light scalar fields. The …