This Wednesday (9 October, 15:00) at B404, we have the Mathematics and Theoretical Physics Seminar as usual, by Sonja Klisch. In addition, at 14:00 at D450, Sonja will give an informal pre-seminar talk geared towards MSc and early PhD students.
Sonja will talk about the double copy (a relation between gauge theory and gravity) and twistors(an auxiliary space in terms on which many gauge theories, such as self-dual Yang–Mills theory, can be naturally formulated). The seminar schedule is available online at https://hertsmathphys.github.io/ .
Speaker: Sonja Klisch (University of Edinburgh)
Title: A double copy from twistor space
Abstract
In this talk I will present a new double copy relation at tree level between gauge theory and gravity amplitudes, graded by helicity.
Amplitudes in gauge theory and gravity in 4d can be partitioned into sectors according to their external helicity configurations. At tree level there are particularly beautiful expressions for these amplitudes coming from twistor strings known as the RSVW (Roiban–Spradlin–Volovich–Witten) formula for gauge theory, and Cachazo–Skinner formula for gravity. At the same time, the double copy gives an explicit relation between gauge theory and gravity amplitudes via GR=(YM)2. However, the explicit representation of the Cachazo-Skinner formula as a double copy of the RSVW formula has long been unknown.
The question answered in this talk is therefore: how do these helicity graded amplitudes manifest the double copy? In the journey there we will discover a new twistorial representation of biadjoint scalars, a way towards the double copy on non‐trivial backgrounds, and the importance of trees.