Curvature expansion of the heat kernel and effective action is derived for quasi-thermal non-vacuum gravitational backgrounds using a covariant generalized Killing vector field.
The "in-in" Formalism and Cosmological Perturbations
5 Pith papers cite this work. Polarity classification is still indexing.
abstract
We describe an efficient scheme for evaluating higher order contributions to primordial cosmological perturbations using the "in-in" formalism, which is the basis of modern calculations of non-Gaussian and higher order contributions to the primordial spectrum. We show that diagrams with two or more vertices require careful handling. We present an implementation of the operator formalism in which these diagrams can be evaluated in a simple and transparent fashion. We illustrate our methodology by evaluating the correction to the primordial gravitational wave spectrum generated by scalar loops, a 2-vertex, 1-loop interaction. We then look at a generalized $N$-point, 2-vertex diagram.
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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.
Residual anomalous coherence in scalar perturbations imprints on scalar-induced tensor modes, producing a correlated gravitational-wave background with nontrivial covariance and phase structure instead of a simple spectral shift.
A new UV in-in algorithm for inflationary loops identifies renormalization difficulties and distinguishable finite corrections to the one-loop bispectrum in EFT inflation.
Classical and quantum correlation functions of inflationary perturbations diverge exponentially with e-folds when interactions are relevant, even if forced to agree at an intermediate time.
citing papers explorer
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Non-vacuum gravitational effective action
Curvature expansion of the heat kernel and effective action is derived for quasi-thermal non-vacuum gravitational backgrounds using a covariant generalized Killing vector field.
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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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Entanglement, Discord, and Residual Coherence in Scalar-Induced Gravitational Waves
Residual anomalous coherence in scalar perturbations imprints on scalar-induced tensor modes, producing a correlated gravitational-wave background with nontrivial covariance and phase structure instead of a simple spectral shift.
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Finite parts of inflationary loops II: A streamlined UV in-in algorithm and distinguishable signatures
A new UV in-in algorithm for inflationary loops identifies renormalization difficulties and distinguishable finite corrections to the one-loop bispectrum in EFT inflation.
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Classical and quantum evolution of inflationary fluctuations
Classical and quantum correlation functions of inflationary perturbations diverge exponentially with e-folds when interactions are relevant, even if forced to agree at an intermediate time.