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A Tree Theorem for Inflation

High Energy Physics - Theory 2009-02-23 v3 Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

Abstract

It is shown that the generating function for tree graphs in the "in-in" formalism may be calculated by solving the classical equations of motion subject to certain constraints. This theorem is illustrated by application to the evolution of a single inflaton field in a Robertson--Walker background.

Cite

@article{arxiv.0805.3781,
  title  = {A Tree Theorem for Inflation},
  author = {Steven Weinberg},
  journal= {arXiv preprint arXiv:0805.3781},
  year   = {2009}
}

Comments

Version accepted for publication in Phys. Rev. D. 22 pages. Some changes to references and clarification in Introduction

R2 v1 2026-06-21T10:43:50.746Z