Cutting rule for in-in correlators and cosmological collider

2024/09/11 by Yohei Ema, Ema, Yohei, Kyohei Mukaida +1 · 2 citations
Computer Science · Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Parallel Computing and Optimization Techniques

paper · pdf · doi:10.48550/arxiv.2409.07521

openalex publication_date 2024/09/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We derive a cutting rule for equal-time in-in correlators including cosmological correlators based on Keldysh r/a basis, which decomposes diagrams into fully retarded functions and cut-propagators consisting of Wightman functions. Our derivation relies only on basic assumptions such as unitarity, locality, and the causal structure of the in-in formalism, and therefore holds for theories with arbitrary particle contents and local interactions at any loop order. As an application, we show that non-local cosmological collider signals arise solely from cut-propagators under the assumption of microcausality. Since the cut-propagators do not contain (anti-)time-ordering theta functions, the conformal time integrals are factorized, simplifying practical calculations.

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