English

Big Steve and the State of the Universe

High Energy Physics - Theory 2023-05-29 v2 History and Philosophy of Physics

Abstract

I share some reminiscences of the late Steven Weinberg. Then I discuss a topic in quantum field theory which he taught me: the role of state wave functionals in deriving the iϵi\epsilon term of the Feynman propagator when using the functional formalism. This is perhaps a curiosity for in-out scattering amplitudes on flat space backgrounds, but it is has much greater significance for the in-in amplitudes of the Schwinger-Keldysh formalism in cosmology. It also touches on the fate, about which Weinberg wondered, of the large logarithms one sometimes finds in quantum corrections from inflationary particle production.

Keywords

Cite

@article{arxiv.2303.05111,
  title  = {Big Steve and the State of the Universe},
  author = {R. P. Woodard},
  journal= {arXiv preprint arXiv:2303.05111},
  year   = {2023}
}

Comments

19 pages, uses LaTeX2e, written for a special issue of Symmetry Commemorating Steven Weinberg. Version 2 slightly revised for publication