2013/07/19 by Edward Witten, Witten, Edward · 5 citations
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #hep-th
paper · pdf · doi:10.48550/arxiv.1307.5124
24 pp.This article is based on a talk presented at the Zuminofest in Berkeley, California, May 2-4, 2013
arxiv created 2013/07/19 · arxiv updated 2013/07/22
The Feynman iε 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.