Résumé |
In this talk, I will present two recent results on string amplitudes.
First, I will explain how a correct computation of the 2-point amplitude
on the sphere matches the expected result from QFT, instead of vanishing
as it was long believed. Second, I will outline the proofs of primitive
analyticity and crossing symmetry for superstring amplitudes to all
orders in perturbation theory. Since these properties are related to
locality and causality in position space in standard QFTs, this opens a
possible window on the nature of the interaction non-locality and how it
fits withing the usual QFT axioms. |