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 mechanical wavefunction of the universe. Here we ask what the imprint of quantum mechanics is on the late time observables. We show that the requirement of unitary time evolution, colloquially the conservation of probabilities, fixes the analytic structure of the wavefunction and of all the cosmological correlators it encodes. In particular, we derive in perturbation theory an infinite set of single-cut rules that generalize the Cosmological Optical Theorem and relate a certain discontinuity of any tree-level $n$-point function to that of lower-point functions. Our rules are closely related to, but distinct from the recently derived Cosmological Cutting Rules. They follow from the choice of the Bunch-Davies vacuum and a simple property of the (bulk-to-bulk) propagator and are astoundingly general: we prove that they are valid for fields with a linear dispersion relation and any mass, any integer spin and arbitrary local interactions with any number of derivatives. They also apply to general FLRW spacetimes admitting a Bunch-Davies vacuum, including de Sitter, slow-roll inflation, power-law cosmologies and even resonant oscillations in axion monodromy. We verify the single-cut rules in a number of non-trivial examples, including four massless scalars exchanging a massive scalar, as relevant for cosmological collider physics, four gravitons exchanging a graviton, and a scalar five-point function.
Reconstructing cosmological correlators via dispersion: from cutting to dressing rules
Indian Institute of Technology Kanpur（坎普尔印度理工学院）；International Centre for Theoretical Sciences (ICTS-TIFR) Tata Institute of Fundamental Research（理论科学国际中心（ICTS-TIFR）塔塔基础研究所）
本文通过色散关系重构宇宙相关函数，利用切割规则和 dressing 规则，揭示了从树级 de Sitter 威滕图到晚期时间片相关函数的联系。
Facultad de Ingeniería, Universidad San Sebastián（圣塞巴斯蒂安大学工程学院）；Departamento de Física, FCFM, Universidad de Chile（智利大学理学院和核物理研究所物理系）；Dipartimento di Fisica, Università di Torino, and INFN Sezione di Torino（都灵大学物理系及意大利国家核物理研究院都灵分部）；Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez（阿道夫·伊巴涅斯大学理工学）
Cosmological Correlator Discontinuities from Scattering Amplitudes
University of Southampton（南安普顿大学）；Imperial College（帝国理工学院）；Durham University（杜伦大学）；University of Amsterdam（阿姆斯特丹大学）；Ludwig-Maximilians-Universität München（慕尼黑大学）
All Tree-Level Massive Cosmological Correlators via Spectral Gluing
Max Planck Institute for Physics, Werner-Heisenberg-Institut（马克斯·普朗克物理研究所，维尔纳·海森堡研究所）；Max Planck-IAS-NTU Center for Particle Physics, Cosmology and Geometry（马克斯·普朗克-IAS-南洋理工大学粒子物理、宇宙学与几何中心）
Propagator positivity bounds for cosmological correlators
Leung Center for Cosmology and Particle Astrophysics, National Taiwan University（国立台湾大学梁中心宇宙学与粒子天体物理学）；Department of Physics and Astronomy, Queen Mary University of London（伦敦玛丽女王大学物理与天文系）
On Cosmological Correlators with Boundary Contributions
The Hong Kong University of Science and Technology（香港科技大学）；Jockey Club Institute for Advanced Study, The Hong Kong University of Science and Technology（香港科技大学赛马会高等研究院）；University of Cambridge（剑桥大学）
Every Wrinkle Carries A Memory: An Integro-differential Bootstrap for Features in Cosmological Correlators
Abdus Salam Centre for Theoretical Physics, Imperial College（阿卜杜斯·萨拉姆理论物理中心，帝国理工学院）；Department of Applied Mathematics and Theoretical Physics, University of Cambridge（剑桥大学应用数学与理论物理系）；Center for Theoretical Physics of the Universe, Institute for Basic Science（基础科学研究院宇宙理论物理中心）
