The two-loop correction to the diffusion coefficient in stochastic inflation is computed for the first time via composite-operator renormalisation and matching in SdSET.
Cosmological Correlators in massless ${\phi}^4$-theory and the Method of Regions
5 Pith papers cite this work. Polarity classification is still indexing.
abstract
The calculation of loop corrections to the correlation functions of quantum fields during inflation or in the de~Sitter background presents greater challenges than in flat space due to the more complicated form of the mode functions. While in flat space highly sophisticated approaches to Feynman integrals exist, similar tools still remain to be developed for cosmological correlators. However, usually only their late-time limit is of interest. We introduce the method-of-region expansion for cosmological correlators as a tool to extract the late-time limit, and illustrate it with several examples for the interacting, massless, minimally coupled scalar field in de~Sitter space. In particular, we consider the in-in correlator $\langle\phi^2(\eta,q)\phi(\eta,k_1)\phi(\eta,k_2)\rangle$, whose region structure is relevant to anomalous dimensions and matching coefficients in Soft de Sitter effective theory.
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citation-polarity summary
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hep-th 5roles
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background 2representative citing papers
Constructs open EFT for stochastic inflation with stochastic RG channel, nonlocal Wilson kernels, and derived master equations matched to full theory via method-of-regions.
Stochastic inflation is the leading infrared limit of a coarse-grained Schwinger–Keldysh effective theory, and the same Fokker–Planck dynamics follows from a Polchinski-type renormalization-group flow for the reduced density matrix.
Different dimensional regularization schemes agree with each other and with unitarity; new analytic eta regulators simplify the work and fix the imaginary part of one-loop coefficients by the logarithmic running of the real part under scale invariance and Bunch-Davies conditions.
Standard SdSET power counting fails for classically conformal φ⁴; leading superhorizon modes must be read from the two-loop anomalous dimension of the two-point function.
citing papers explorer
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Quantum correction to the diffusion term in stochastic inflation from composite-operator matching in Soft de Sitter Effective Theory
The two-loop correction to the diffusion coefficient in stochastic inflation is computed for the first time via composite-operator renormalisation and matching in SdSET.
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Stochastic inflation as an open quantum system II: open effective field theory and stochastic matching
Constructs open EFT for stochastic inflation with stochastic RG channel, nonlocal Wilson kernels, and derived master equations matched to full theory via method-of-regions.
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Stochastic inflation from a non-equilibrium renormalization group
Stochastic inflation is the leading infrared limit of a coarse-grained Schwinger–Keldysh effective theory, and the same Fokker–Planck dynamics follows from a Polchinski-type renormalization-group flow for the reduced density matrix.
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Unitary and Analytic Renormalisation of Cosmological Correlators
Different dimensional regularization schemes agree with each other and with unitarity; new analytic eta regulators simplify the work and fix the imaginary part of one-loop coefficients by the logarithmic running of the real part under scale invariance and Bunch-Davies conditions.
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Classical conformal invariance and superhorizon dynamics in de Sitter
Standard SdSET power counting fails for classically conformal φ⁴; leading superhorizon modes must be read from the two-loop anomalous dimension of the two-point function.