Develops open EFT for stochastic inflation with a distinct stochastic RG channel, derives nonlocal master equations including Fokker-Planck and Klein-Kramers forms, and demonstrates stochastic renormalization with an analytic regulator.
The separate universe approach and the evolution of nonlinear superhorizon cosmological perturbations
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
In this letter we review the separate universe approach for cosmological perturbations and point out that it is essentially the lowest order approximation to a gradient expansion. Using this approach, one can study the nonlinear evolution of inhomogeneous spacetimes and find the conditions under which the long wavlength curvature perturbation can vary with time. When there is one degree of freedom or a well-defined equation of state the nonlinear long wavelength curvature perturbation remains constant. With more degrees of freedom it can vary and this variation is determined by the non-adiabatic pressure perturbation, exactly as in linear theory. We identify combinations of spatial vectors characterizing the curvature perturbation which are invariant under a change of time hypersurfaces.
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Derives stochastic equations from Schwinger-Keldysh formalism that include quantum diffusion and classical metric perturbations for non-perturbative ultra-slow-roll inflation, validated on Starobinsky and critical Higgs models.
Ward identities derived from perturbation-theory symmetries enforce non-perturbative constraints on the infrared power spectrum and guarantee conservation of super-horizon modes in non-attractor inflation.
citing papers explorer
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Stochastic inflation as an open quantum system II: open effective field theory and stochastic matching
Develops open EFT for stochastic inflation with a distinct stochastic RG channel, derives nonlocal master equations including Fokker-Planck and Klein-Kramers forms, and demonstrates stochastic renormalization with an analytic regulator.
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Nonperturbative stochastic inflation in perturbative dynamical background
Derives stochastic equations from Schwinger-Keldysh formalism that include quantum diffusion and classical metric perturbations for non-perturbative ultra-slow-roll inflation, validated on Starobinsky and critical Higgs models.
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Ward Identity Constraints on Loop Corrections in Non-Attractor Inflation
Ward identities derived from perturbation-theory symmetries enforce non-perturbative constraints on the infrared power spectrum and guarantee conservation of super-horizon modes in non-attractor inflation.