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Related papers: Schwinger-Keldysh Cosmological Cutting Rules

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Primordial perturbations in our universe are believed to have a quantum origin, and can be described by the wavefunction of the universe (or equivalently, cosmological correlators). It follows that these observables must carry the imprint…

High Energy Physics - Theory · Physics 2021-06-16 Scott Melville , Enrico Pajer

We derive discontinuity relations, also known as cutting rules, and explore the analytic properties of cosmological correlators, fundamental observables of the primordial universe. Our emphasis is on how these relations arise from unitarity…

High Energy Physics - Theory · Physics 2025-12-25 Shibam Das , Debanjan Karan , Babli Khatun , Nilay Kundu

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…

High Energy Physics - Theory · Physics 2024-12-11 Yohei Ema , Kyohei Mukaida

A number of diagrammatic "cutting rules" have recently been developed for the wavefunction of the Universe which determines cosmological correlation functions. These leverage perturbative unitarity to relate particular "discontinuities" in…

High Energy Physics - Theory · Physics 2023-08-02 Santiago Agui-Salcedo , Scott Melville

Using cosmological dressing rules, we uplift flat-space unitarity cuts to discontinuity relations for dS/EAdS observables. In this representation, Cutkosky delta functions map directly to "Disc" operations in the exchanged energy variable.…

High Energy Physics - Theory · Physics 2026-01-15 Arhum Ansari , Sachin Jain , Deep Mazumdar

The initial conditions of our universe appear to us in the form of a classical probability distribution that we probe with cosmological observations. In the current leading paradigm, this probability distribution arises from a quantum…

High Energy Physics - Theory · Physics 2021-08-11 Harry Goodhew , Sadra Jazayeri , Mang Hei Gordon Lee , Enrico Pajer

Both the Wavefunction of the Universe and the Schwinger-Keldysh in-in formalism are central tools for analyzing primordial cosmological observables, such as equal-time correlation functions. While their conceptual equivalence is well…

High Energy Physics - Theory · Physics 2026-01-21 Gonzalo A. Palma

Recent theoretical work has revealed that basic observables of quantum field theory in de Sitter space, known as in-in or cosmological correlators, exhibit surprisingly simple mathematical structure reminiscent of scattering amplitudes in…

High Energy Physics - Theory · Physics 2026-02-04 Chandramouli Chowdhury , Sadra Jazayeri , Arthur Lipstein , Joe Marshall , Jiajie Mei , Ivo Sachs

The basic observables in cosmology are known as in-in correlators. Recent calculations have revealed that in-in correlators in four dimensional de Sitter space exhibit hidden simplicity stemming from a close relation to scattering…

High Energy Physics - Theory · Physics 2026-03-12 Chandramouli Chowdhury , Arthur Lipstein , Joe Marshall , Jiajie Mei , Ivo Sachs

In this work, we investigate how cosmological correlators can be reconstructed by applying the momentum-space dispersion formula to their discontinuities, treating them as functions of momentum variables associated with the corresponding de…

High Energy Physics - Theory · Physics 2026-02-06 Shibam Das , Debanjan Karan , Babli Khatun , Nilay Kundu

The field theoretic wavefunction in cosmological spacetimes has received much attention as a fundamental object underlying the generation of primordial perturbations in our universe. Assuming an initial Bunch-Davies state, unitary time…

High Energy Physics - Theory · Physics 2025-01-09 Diptimoy Ghosh , Enrico Pajer , Farman Ullah

Cosmological correlators are fundamental observables in an expanding universe and are highly non-trivial functions even at tree-level. In this work, we uncover novel structures in the space of such tree-level correlators that enable us to…

High Energy Physics - Theory · Physics 2025-03-11 Thomas W. Grimm , Arno Hoefnagels , Mick van Vliet

Cosmological correlators encode invaluable information about the wavefunction of the primordial universe. In this letter we present a duality between correlators and wavefunction coefficients that is valid to all orders in the loop…

High Energy Physics - Theory · Physics 2025-01-07 David Stefanyszyn , Xi Tong , Yuhang Zhu

Cosmological correlators, the natural observables of the primordial universe, have been extensively studied in the past two decades using the in-in formalism pioneered by Schwinger and Keldysh for the study of dissipative open systems.…

High Energy Physics - Theory · Physics 2024-02-28 Yaniv Donath , Enrico Pajer

We are investigating if the double copy structure as product of scattering amplitudes of gauge theories applies to cosmological correlators computed in a class of theories for inflation by the operatorial version of the In-In formalism of…

High Energy Physics - Theory · Physics 2020-05-06 A. R. Fazio

In-in correlators are the basic observables in cosmology and are traditionally computed using the Schwinger-Keldysh formalism. In this paper we revisit this formalism for photons, gluons, and gravitons coupled to scalars in four dimensional…

High Energy Physics - Theory · Physics 2025-12-17 Chandramouli Chowdhury , Arthur Lipstein , Joe Marshall , Alex Jiayi Zhang

Cosmological correlation functions are significantly more complex than their flat-space analogues, such as tree-level scattering amplitudes. While these amplitudes have simple analytic structure and clear factorisation properties,…

High Energy Physics - Theory · Physics 2024-09-04 Denis Werth

In this work we perform a systematic study of the singularity structure of inflationary correlations at 1-loop. We explicitly compute a few diagrams and find a pattern emerging in the singularities produced. Motivated by this, we derive…

High Energy Physics - Theory · Physics 2025-03-31 Supritha Bhowmick , Mang Hei Gordon Lee , Diptimoy Ghosh , Farman Ullah

Cosmological fluctuations retain a memory of the physics that generated them in their spatial correlations. The strength of correlations varies smoothly as a function of external kinematics, which is encoded in differential equations…

High Energy Physics - Theory · Physics 2024-07-04 Nima Arkani-Hamed , Daniel Baumann , Aaron Hillman , Austin Joyce , Hayden Lee , Guilherme L. Pimentel

The Cutkosky cutting rules establish a direct connection between the imaginary parts of loop amplitudes and physical observables such as decay rates and cross sections, providing heuristic insights into the underlying processes. This work…

High Energy Physics - Phenomenology · Physics 2026-02-03 Zheng-Liang Liang , Fawei Zheng
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