The authors define a locality condition for hard-mode states during inflation that unifies local effective dynamics for soft modes, suppression of loop corrections, generalized soft theorems, and absence of infrared divergences in observable correlators.
In-in and $\delta N$ calculations of the bispectrum from non-attractor single-field inflation
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
In non-attractor single-field inflation models producing a scale-invariant power spectrum, the curvature perturbation on super-horizon scales grows as ${\cal R}\propto a^3$. This is so far the only known class of self-consistent single-field models with a Bunch-Davies initial state that can produce a large squeezed-limit bispectrum violating Maldacena's consistency relation. Given the importance of this result, we calculate the bispectrum with three different methods: using quantum field theory calculations in two different gauges, and classical calculations (the $\delta N$ formalism). All the results agree, giving the local-form bispectrum parameter of $f^{local}_{NL}=5(1+c_s^2)/(4c_s^2)$. This result is valid for arbitrary values of the speed of sound parameter, $c_s$, for a particular non-attractor model we consider in this paper.
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Derives all-order Hamiltonians via EFT of inflation for USR models and shows L-loop corrections to CMB-scale perturbations scale as (ΔN P_e L)^L, exiting perturbative control at L=4 for typical ΔN≈2.5.
Tree-level multi-soft theorems for scalar and graviton correlation functions are derived at leading soft order via background-wave coordinate rescaling, including tensor exchanges in scalars and scalar exchanges in tensors.
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Locality in effective field theory for inflationary soft modes
The authors define a locality condition for hard-mode states during inflation that unifies local effective dynamics for soft modes, suppression of loop corrections, generalized soft theorems, and absence of infrared divergences in observable correlators.
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Hamiltonians to all Orders in Perturbation Theory and Higher Loop Corrections in Single Field Inflation with PBHs Formation
Derives all-order Hamiltonians via EFT of inflation for USR models and shows L-loop corrections to CMB-scale perturbations scale as (ΔN P_e L)^L, exiting perturbative control at L=4 for typical ΔN≈2.5.
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Multi-soft theorems for cosmological correlators: Background wave method for scalars & gravitons
Tree-level multi-soft theorems for scalar and graviton correlation functions are derived at leading soft order via background-wave coordinate rescaling, including tensor exchanges in scalars and scalar exchanges in tensors.