A Laplace-space representation converts massive single-exchange cosmological correlators in de Sitter into a rapidly convergent series derived from flat-space integrals.
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Inflation Correlators with Multiple Massive Exchanges
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abstract
The most general tree-level boundary correlation functions of quantum fields in inflationary spacetime involve multiple exchanges of massive states in the bulk, which are technically difficult to compute due to the multi-layer nested time integrals in the Schwinger-Keldysh formalism. On the other hand, correlators with multiple massive exchanges are well motivated in cosmological collider physics, with the original quasi-single-field inflation model as a notable example. In this work, with the partial Mellin-Barnes representation, we derive a simple rule, called family-tree decomposition, for directly writing down analytical answers for arbitrary nested time integrals in terms of multi-variable hypergeometric series. We present the derivation of this rule together with many explicit examples. This result allows us to obtain analytical expressions for general tree-level inflation correlators with multiple massive exchanges. As an example, we present the full analytical results for a range of tree correlators with two massive exchanges.
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A Kontorovich-Lebedev-Fourier space is built for (d+1)-dimensional de Sitter correlators from the Casimir operator of SO(1,d+1), producing rational propagators and Feynman rules that turn tree and loop diagrams into spectral integrals and orthogonality relations.
The double-exchange cosmological correlator is computed in KLF space, yielding a double series over hypergeometric functions that improves on prior four-layer representations.
Laplace transform converts cosmological correlator diagrams into flat-space integrals against kernels, yielding a closed-form rapidly convergent series for the massive single-exchange case valid across the full kinematic domain.
Introduces spectral dispersion bootstrap combining dS spectral decomposition and dispersion relations to compute 3- and 4-point loop correlators with massive scalar and vector exchanges.
Exact fermionic bubble loop signals in cosmological collider physics are obtained via spectral and Mellin-Barnes methods, with the Yukawa bispectrum vanishing identically due to field redefinition.
A parity-split IBP system for n-propagator families in de Sitter space is identified, along with a conjecture that dlog-form differential equations extend to dS integrands with Hankel functions, verified for the one-loop bubble.
Chemical potential from a unique dim-5 inflaton–right-handed-neutrino operator softens heavy-mass Boltzmann suppression and amplifies helicity-dependent oscillatory non-Gaussianity from the fermion triangle loop.
Unified tree-level bispectrum shapes for cosmological collider processes are computed and searched in Planck data, yielding no detection but a weak hint for chemical potential extensions at ω - M ≃ 3H.
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
In dynamical Chern-Simons inflation the parity-odd trispectrum is a double copy of the mixed bispectrum and parity-odd power spectrum via a prior factorization formula.
citing papers explorer
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Massive Cosmological Correlators from Flat Space: a Laplace-Space Approach
A Laplace-space representation converts massive single-exchange cosmological correlators in de Sitter into a rapidly convergent series derived from flat-space integrals.
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Kontorovich-Lebedev-Fourier Space for de Sitter Correlators
A Kontorovich-Lebedev-Fourier space is built for (d+1)-dimensional de Sitter correlators from the Casimir operator of SO(1,d+1), producing rational propagators and Feynman rules that turn tree and loop diagrams into spectral integrals and orthogonality relations.
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Cosmological Correlators in KLF and the Double-Exchange
The double-exchange cosmological correlator is computed in KLF space, yielding a double series over hypergeometric functions that improves on prior four-layer representations.
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Laplace Space for Cosmological Correlators
Laplace transform converts cosmological correlator diagrams into flat-space integrals against kernels, yielding a closed-form rapidly convergent series for the massive single-exchange case valid across the full kinematic domain.
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On-Shell Bootstrap of Loop Inflation Correlators with Spectral Dispersion
Introduces spectral dispersion bootstrap combining dS spectral decomposition and dispersion relations to compute 3- and 4-point loop correlators with massive scalar and vector exchanges.
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Fermionic Bubble Loop in Cosmological Collider Revisited: Exact signals from spectral and Mellin-Barnes methods
Exact fermionic bubble loop signals in cosmological collider physics are obtained via spectral and Mellin-Barnes methods, with the Yukawa bispectrum vanishing identically due to field redefinition.
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Loop integrals in de Sitter spacetime: The parity-split IBP system and $\mathrm{d}\log$-form differential equations
A parity-split IBP system for n-propagator families in de Sitter space is identified, along with a conjecture that dlog-form differential equations extend to dS integrands with Hankel functions, verified for the one-loop bubble.
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Cosmological Collider Signatures from Right-Handed Neutrino Loop
Chemical potential from a unique dim-5 inflaton–right-handed-neutrino operator softens heavy-mass Boltzmann suppression and amplifies helicity-dependent oscillatory non-Gaussianity from the fermion triangle loop.
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Scalars at the Cosmological Collider: Full Shapes of Tree Diagrams and Bispectrum Searches using Planck Data
Unified tree-level bispectrum shapes for cosmological collider processes are computed and searched in Planck data, yielding no detection but a weak hint for chemical potential extensions at ω - M ≃ 3H.
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Massive Exchange and the Sign of the Equilateral Bispectrum
The equilateral bispectrum from massive scalar exchange in inflation is not universally negative in the full EFT of inflation; its sign depends on a critical ratio of operator coefficients.
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A Match Made in Heaven: Linking Observables in Inflationary Cosmology
In dynamical Chern-Simons inflation the parity-odd trispectrum is a double copy of the mixed bispectrum and parity-odd power spectrum via a prior factorization formula.