UV divergences of one-loop primordial tensor and scalar spectra are absorbed by covariant and tadpole counterterms using only the universal WKB expansion of internal modes, yielding finite model-independent renormalized expressions.
Matching second-order classical and 1-loop quantum tensor power spectra in de Sitter spacetime
2 Pith papers cite this work. Polarity classification is still indexing.
abstract
Large corrections to the inflationary tensor power spectrum have been speculated to emerge either as second-order scalar-induced classical effects, or as 1-loop quantum corrections. These two sources are not independent of each other. Choosing the example of a massless minimally coupled scalar field, we show how the full 1-loop result can be divided into its classical and vacuum parts. Working first in dimensional regularization, we show that the classical part is IR divergent, with IR referring to small comoving momenta that have an influence for a very long time. In the full 1-loop quantum result, these divergences cancel. Introducing then a momentum cutoff that permits for a numerical evaluation of the classical contribution, we show that the IR sensitivity manifests itself as a cubic divergence. We suggest a procedure of "non-perturbative renormalization" for extracting physical information not affected by the divergence. If this can be implemented in realistic systems, it could consolidate numerical studies of inflationary scalar-induced gravitational waves.
years
2026 2representative citing papers
A tutorial deriving cosmological perturbation equations from inflation through reheating, with explicit gauge-invariant computations and Python scripts.
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Background-independent one-loop renormalization of tensor and scalar primordial spectra
UV divergences of one-loop primordial tensor and scalar spectra are absorbed by covariant and tadpole counterterms using only the universal WKB expansion of internal modes, yielding finite model-independent renormalized expressions.
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From inflation to hot big bang -- a tutorial on cosmological perturbations
A tutorial deriving cosmological perturbation equations from inflation through reheating, with explicit gauge-invariant computations and Python scripts.