The Feynman $i \epsilon$ in String Theory
High Energy Physics - Theory
2013-07-22 v1
Abstract
The Feynman is an important ingredient in defining perturbative scattering amplitudes in field theory. Here we describe its analog in string theory. Roughly one takes the string worldsheet to have Lorentz signature when a string is going on-shell although it has Euclidean signature generically.
Keywords
Cite
@article{arxiv.1307.5124,
title = {The Feynman $i \epsilon$ in String Theory},
author = {Edward Witten},
journal= {arXiv preprint arXiv:1307.5124},
year = {2013}
}
Comments
24 pp.This article is based on a talk presented at the Zuminofest in Berkeley, California, May 2-4, 2013